WO2004002513A2

WO2004002513A2 - Proteins involved in the regulation of energy homeostasis

Info

Publication number: WO2004002513A2
Application number: PCT/EP2003/007007
Authority: WO
Inventors: Karsten Eulenberg; Tri Nguyen; Thomas HÄDER; Günter BRÖNNER
Original assignee: DeveloGen Aktiengesellschaft für entwicklungsbiologische Forschung
Priority date: 2002-07-01
Filing date: 2003-07-01
Publication date: 2004-01-08
Also published as: AU2003253021A1; WO2004002513A3

Abstract

The present invention discloses novel uses for energy homeostasis regulating proteins and polynucleotides encoding these in the diagnosis, study, prevention, and treatment of metabolic diseases and disorders.

Description

Proteins involved in the regulation of energy homeostasis

Description

This invention relates to the use of nucleic acid sequences encoding Dgk epsilon, synaptojanin, G alpha 49B, CG13609, Rab8, Delta, Nup214, Malvolio, or Fasciclin 1 homologous proteins, to the use of polynucleotides encoding these, and to the use of effectors/modulators of the proteins and polynucleotides in the diagnosis, study, prevention, and treatment of diseases and disorders related to body-weight regulation, for example, but not limited to, metabolic diseases or dysfunctions such as obesity, metabolic syndrome, diabetes mellitus, eating disorder, cachexia, pancreatitis, hypertension, coronary heart disease, hypercholesterolemia, dyslipidemia, osteoarthritis, gallstones, or liver fibrosis.

There are several metabolic diseases of human and animal metabolism, eg., obesity and severe weight loss, that relate to energy imbalance where caloric intake versus energy expediture is imbalanced. Obesity is one of the most prevalent metabolic disorders in the world. It is still a poorly understood human disease that becomes more and more relevant for western society. Obesity is defined as a body weight more than 20% in excess of the ideal body weight, frequently resulting in a significant impairment of health. Obesity may be measured by body mass index, an indicator of adiposity or fatness. Further parameters for defining obesity are waist circumferences, skinfold thickness and bioimpedance. Obesity is associated with an increased risk for cardiovascular disease, hypertension, diabetes, hyperlipidaemia and an increased mortality rate. Besides severe risks of illness, individuals suffering from obesity are often isolated socially. Obesity is influenced by genetic, metabolic, biochemical, psychological, and behavioral factors, and can be caused by different reasons such as non-insulin dependent diabetes, increase in triglycerides, increase in carbohydrate bound energy and low energy expenditure. As such, it is a complex disorder that must be addressed on several fronts to achieve lasting positive clinical outcome. Since obesity is not to be considered as a single disorder but as a heterogeneous group of conditions with (potential) multiple causes, it is also characterized by elevated fasting plasma insulin and an exaggerated insulin response to oral glucose intake (Koltermann J., (1980) Clin. Invest 65, 1272-1284). A clear involvement of obesity in type 2 diabetes mellitus can be confirmed (Kopelman P.G., (2000) Nature 404, 635-643).

Hyperlipidemia and elevation of free fatty acids correlate clearly with the metabolic syndrome, which is defined as the linkage between several diseases, including obesity and insulin resistance. This often occurs in the same patients and are major risk factors for development of type 2 diabetes and cardiovascular disease. It was suggested that the control of lipid levels and glucose levels is required to treat type 2 diabetes, heart disease, and other occurances of metabolic syndrome (see, for example, Santomauro A. T. et al., (1999) Diabetes, 48(9): 1836-1841 and McCook, (2002), JAMA 288:2709-2716).

The molecular factors regulating food intake and body weight balance are incompletely understood. Even if several candidate genes have been described which are supposed to influence the homeostatic system(s) that regulate body mass/weight, like leptin or the peroxisome proliferator-activated receptor-gamma co-activator, the distinct molecular mechanisms and/or molecules influencing obesity or body weight/body mass regulations are not known. In addition, several single-gene mutations resulting in obesity have been described in mice, implicating genetic factors in the etiology of obesity (Friedman and Leibel, 1990, Cell 69: 217-220). ln the obese (ob) mouse, a single gene mutation (obese) results in profound obesity, which is accompanied by diabetes (Friedman et. al., 1991 , Genomics 1 1 : 1054-1062).

Therefore, the technical problem underlying the present invention was to provide for means and methods for modulating/effecting (pathological) metabolic conditions influencing body-weight regulation and/or energy homeostatic circuits. The solution to said technical problem is achieved by providing the embodiments characterized in the claims. Accordingly, the present invention relates to novel functions of proteins and nucleic acids encoding these in body-weight regulation, energy homeostasis, metabolism, and obesity. The proteins disclosed herein and polynucleotides encoding these are thus suitable to investigate metabolic diseases and disorders. Further new compositions are provided that are useful in diagnosis, treatment, and prognosis of metabolic diseases and disorders as described.

So far, it has not been described that the proteins of the invention and homologous proteins are involved in the regulation of energy homeostasis and body-weight regulation and related disorders, and thus, no functions in metabolic diseases or dysfunctions and other diseases as listed above have been discussed. In this invention, we demonstrate that the correct gene dose of a protein of the invention is essential for maintenance of energy homeostasis. A genetic screen was used to identify that mutations of a gene encoding a protein of the invention or a homologous gene causes changes in the metabolism, in particular related to obesity, which is reflected by a significant change in the triglyceride content, the major energy storage substance.

Before the present proteins, nucleotide sequences, and methods are described, it is understood that this invention is not limited to the particular methodology, protocols, cell lines, vectors, and reagents described as these may vary. It is also to be understood that the terminology used herein is for the purpose of describing particular embodiments only, and is not intended to limit the scope of the present invention that will be limited only by the appended claims. Unless defined otherwise, all technical and scientific terms used herein have the same meanings as commonly understood by one of ordinary skill in the art to which this invention belongs. Although any methods and materials similar or equivalent to those described herein can be used in the practice or testing of the present invention, the preferred methods, devices, and materials are now described. All publications mentioned herein are incorporated herein by reference for the purpose of describing and disclosing the cell lines, vectors, and methodologies that are reported in the publications which might be used in connection with the invention. Nothing herein is to be construed as an admission that the invention is not entitled to antedate such disclosure.

The present invention discloses that Dgk epsilon (GadFly Accession Number CG8657), synaptojanin (GadFly Accession Number CG6562), G alpha 49B (GadFly Accession Number CG17759), CG13609 (GadFly Accession Number), Rab8 (GadFly Accession Number CG8287), Delta (GadFly Accession Number CG3619), Nup214 (GadFly Accession Number CG3820), Malvolio (GadFly Accession Number CG3671 ), or Fasciclin 1 (GadFly Accession Number CG6588) and homologous proteins (herein referred to as "proteins of the invention" or "a protein of the invention") are regulating the energy homeostasis and fat metabolism, especially the metabolism and storage of triglycerides, and polynucleotides, which identify and encode the proteins disclosed in this invention. The invention also relates to vectors, host cells, effectors/modulators of the polypeptides and polynucleotides, e.g. antibodies, and recombinant methods for producing the polypeptides and polynucleotides of the invention. The invention also relates to the use of these compounds in the diagnosis, study, prevention, and treatment of metabolic diseases or dysfunctions, including metabolic syndrome, obesity, and/or diabetes as well as related disorders such as eating disorder, cachexia, hypertension, coronary heart disease, hypercholesterolemia, dyslipidemia, osteoarthritis, gallstones, or liver fibrosis.

Diacylglycerol kinase (DGK) is one of the key enzymes involved in the regulation of signal transduction. It attenuates protein kinase C (PKC) activity and cell cycle progression of T-lymphocytes, through controlling the intracellular levels of the second messengers, diacylglycerol and phosphatidic acid. Eight DGK isozymes containing characteristic zinc finger structures in common have been identified (see, for example, Sakane F. and Kanoh H., (1997) Int J Biochem Cell Biol 29(10): 1 139-1 143; Tang W. et al., (1996) J Biol Chem 1996 Apr 26.271 (17):10237-41 ).

DGK attenuates levels of the second messenger diacylglycerol (DG) by converting it to phosphatidic acid. DGK epsilon specifically phosphorylates polyunsaturated DG in vivo and thereby regulates PKC localization and activity. Polyunsaturated DG functions as messenger and DGK epsilon is a physiological terminator of DG second messenger signaling (Pettitt T. R. and Wakelam M.J., (1999) J Biol Chem 274(51 ):36181 -6). DGK epsilon regulates seizure susceptibility and long-term potentiation through arachidonoyl- inositol lipid signaling. Therefore, DGK epsilon contributes to modulate neuronal signaling pathways linked to synaptic activity, neuronal plasticity, and epileptogenesis (Rodriguez de Turco E. B. et al., (2001 ) Proc Natl Acad Sci U S A 98(8):4740-4745).

A search for disease gene linkage revealed that a locus for autosomal dominant retinitis pigmentosa known as RP17 resided in the region of human diacylglycerol kinase epsilon (Tang W et al., (1999) Gene 239(1 ):185-192). Synaptic vesicles are recycled with remarkable speed and precision in nerve terminals. A major recycling pathway involves clathrin-mediated endocytosis at endocytic zones located around sites of release. Different 'accessory' proteins linked to this pathway have been shown to alter the shape and composition of lipid membranes, to modify membrane-coat protein interactions, and to influence actin polymerization. These include the GTPase dynamin, the lysophosphatidic acid acyl transferase endophilin, and the phosphoinositide phosphatase synaptojanin (Brodin L. et al., (2000) Curr Opin Neurobiol 10(3):312-320). Rat synaptojanin has 5-phosphatase activity, and its N-terminal domain is homologous with the yeast protein Sad (RsdD, which is genetically implicated in phospholipid metabolism and in the function of the actin cytoskeleton. Synaptojanin also binds the SH3 domain of amphiphysin, a presynaptic protein with a putative function in endocytosis. These data suggested a link between phosphoinositide metabolism and synaptic vesicle recycling (McPherson P. S. et al., (1996) Nature 379:353-357). Interestingly, Synaptojanin 1 -deficient mice exhibit neurological defects and die shortly after birth.

The Drosophila Delta (DI) gene is essential for cell-cell communication regulating the determination of various cell fates during development. DI encodes a transmembrane protein, with epidermal-growth-factor-like repeats in the extracellular domain. Interestingly, D1 directly interacts with a transmembrane protein with similar structural features, Notch, in a ligand-receptor-like manner. The mouse Delta-like gene 1 (DIM ) is transiently expressed during gastrulation and early organogenesis, and in a tissue-restricted manner in adult animals (in lung and heart). In mammalian embryos, Delta- like proteins are involved in cell-to-cell communication.

Thus, it was suggested that Delta-like proteins play a role in cellular interactions underlying somitogenesis and development of the nervous system (Bettenhausen B. et al., (1995) Development 121 (8):2407-2418). The mouse Delta homologue DIM is involved in the compartmentalization of somites and maintenance of somite borders in mice (Hrabe de Angelis M. et al., (1997) Nature 386(6626):717-721 ). Mice deficient for DII1 showed accelerated differentiation of pancreatic endocrine cells (Apelqvist A. et al., (1999) Nature 400(6747):877-881 ).

The Drosophila gene G alpha 49B encodes the alpha subunit of a heteromeric G-protein GTPase involved in phospolipase C activation. As shown in this invention, G alpha 49B is most homologous to the human and mouse guanine nucleotide binding protein (G protein), q polypeptide (GnaQ or G alpha q), and human guanine nucleotide binding protein (G protein), alpha 1 1 (Gna1 1 or G alpha 1 1 ).

G proteins are involved as modulators or transducers in various transmembrane signalling systems. G proteins are composed of 3 units (alpha, beta and gamma). The alpha chain contains the guanine nucleotide binding site. G protein alpha subunits are encoded by a multigene family of 16 genes that can be grouped into four classes (Gq, Gs, Gi, and G12). The Gq class is composed of four ubiquitously expressed genes in mouse and human, including Gna1 1 (G alpha 1 1 ) and Gnaq (G alpha q) (see for example, Davignon I. et al., 1996, Genomics 31 (3):359-366, Magovcevic I. et al., 1995, Hear Res 90(1 -2):55-64).

Heterotrimeric G proteins of the Gq class are involved in signaling pathways regulating cardiac growth and development under physiological and pathological conditions. Knockout mice carrying inactivating mutations in G alpha q and G alpha 1 1 demonstrate that at least two active alleles of these genes are required for extrauterine life (Offermanns S. et al., 1998, EMBO J 17(15):4304-4312).

The guanine nucleotide-binding proteins G alpha q and G alpha 1 1 produce receptor regulation of phospholipase C and are expressed in hamster brown adipose tissue (BAT) at the same levels. Cold acclimation results in reduction of the plasma membrane levels of these G alpha proteins (Bourova L. et al., 1999, J Mol Endocrinol 23(2):223-229). The concentrations of G alpha q and G alpha 1 1 were significantly greater in adipocyte membranes from the diabetic (db/db) mice than in membranes from their lean non-diabetic littermate controls. Most of the selective changes in G-protein subunit production in adipocytes from this animal model of type 2 diabetes may be due to other endocrine or metabolic abnormalities associated with the diabetic phenotype (Rodgers B. D. et al., 2001 , J Endocrinol 168(3):509-515).

The Drosophila gene CG 13609 (GadFly Accession Number) encodes a protein with unknown function. As shown in this invention, CG13609 is most homologous to the human and mouse proteins encoded by prostate tumor over expressed gene 1 (PTOV1 ). PTOV1 is overexpressed in protstate tumors at levels significantly higher than benign prostatic hyperplasia or normal prostate tissue. PTOV1 is expressed abundantly in normal human brain, heart, skeletal muscle, kidney and liver, and at low levels in normal prostate and shows a perinuclear localization (Benedit P. et al., 2001 , Oncogene 20(12): 1455-1464). A class-l aminoacyl-tRNA synthetase signature has been predicted for one splice variant of the PTOV1 gene (see GenBank Accession Number AX077798.1 , Sequence 29 from patent WO0107628). Rab proteins are a family of small GTPases that regulate intracellular vesicle traffic. Rab8 is a small Ras-like GTPase that regulates polarized membrane transport to the basolateral membrane in epithelial cells and to the dendrites in neurons. Rab8 promotes polarized membrane transport through reorganization of actin and microtubules in fibroblasts (Peranen J. et al. (1996) J Cell Biol 135(1 ):153-167). The GTPase Rab8b, because of its homology with Rab8, has been suggested to function in vesicle transport to the plasma membrane. Rabδb has a stimulatory effect on cAMP-induced secretion of the adrenocorticotropic hormone ACTH and is involved in regulated secretion (Chen S. et al. (2001 ) J Biol Chem 276(16): 13209-13216).

In its active form, the GTP-binding protein Rab8 interacts with a stress-activated protein kinase. Rab8 is present in the cytosol and as a peripheral membrane protein concentrated in the Golgi region and basolateral plasma membrane domains where it is involved in vesicular traffic (Ren M. et al. (1996) Proc Natl Acad Sci U S A 93(10):5151 -5155). A deficiency of Rab8 inhibits membrane traffic in developing neurons (Huber L. A. et al., (1995) Mol Cell Biol 15(2):918-924). Rab8 in retinal photoreceptors may participate in rhodopsin transport and in rod outer segment disk morphogenesis (Deretic D. et al., (1995) J Cell Sci 1995 Jan; 108 ( Pt 1 ):215-24).

Nup214 (nucleoporin 214 kD) is a component of a nuclear pore complex (NPC) that mediates the bidirectional movement of macromolecules between the nucleus and the cytoplasm (Bodoor K. et al., (1999) Biochem Cell Biol 77(4):321 -329). Nup214 is essential for NPC function in mouse embryos and is critical to cell cycle progression and required for both nuclear protein import and mRNA export (Van Deursen J. et al.,(1996) EMBO J 15(20):5574-5583). Overexpression of the nucleoporin Nup214 induces growth arrest, nucleocytoplasmic transport defects, and apoptosis (Boer J. et al., (1998) Mol Cell Biol 18(3): 1236-1247). Nup214 is involved in myeloid leukemia in humans.

It has been described that the expression level of Nup214 is related to the amount of the intraperitoneal adipose tissue (see, for example, patent application JP2001008699). However, although the use of Nup214 in an analytical process for the estimation of the amount of intraperitoneal adipose tissue was described in the prior art, it has not been described in the prior art that Nup214 is directly involved in the regulation of energy homoestasis and thus involved in the storage of triglycerides. The Malvolio (Mvl) gene was originally identified in a screen for mutants that affect taste behavior. Mutants exhibit altered gustatory behavior and are defective in the neural pathway processing or discriminating gustatory information (Cellier M. et al., (1995) Proc Natl Acad Sci U S A. 92(22): 10089-10093). The natural resistance-associated macrophage protein (NRAMP) family consists of Nrampl , Nramp2, and yeast proteins Smf1 and Smf2. The NRAMP family is a family of functionally related proteins defined by a conserved hydrophobic core of ten transmembrane domains (Cellier M., supra). Nrampl is expressed exclusively in cells of the immune system such as macrophages and leukocytes and is recruited to the membrane of a phagosome upon phagocytosis. Nrampl confers resistance to a variety of intracellular pathogens (Jabado N. et al., (2000) J Exp Med 192(9):1237-1248). Nrampl and Nramp2 have been described as divalent amphoteric cation transporter for Fe²⁺, Mn²⁺ and Zn²⁺ amongst others (Agranoff D.D. and Krishna S., (1998) Mol. Microbiol. 28:403-412). Nramp2 is expressed at high levels in the intestine and is the major transferrin-independent iron uptake system in mammals (Govoni G. and Gros P., (1998) Inflamm Res 47(7):277-284).

Drosophila Fasciclin 1 encodes for a cell adhesion molecule involved in neuronal cell adhesion, which is a component of the plasma membrane. It is involved in growth cone guidance in the embryonic insect nervous system (Wang W. C. et al., (1993) J Biol Chem 268(2): 1448-1455). Fasciclin 1 is most homologous to human osteoblast specific factor 2 (OSF2, see Takeshita, Biochem J. 1993, 294 ( Pt 1 ):271 -8) and human transforming growth factor, beta-induced, 68 kD. Osteoblast specific factor 2 (periostin) is a secreted protein that is highly expressed in early osteoblastic cells in vitro and in periosteum and periodontal ligament tissues in vivo. It is known that OSF-2 supports cellular adhesion and spreading in vitro and that it plays a role in in the progression of different tumors. OSF-2 plays an important role in the formation of bone, by acting as a growth factor or adhesion or "guiding" protein to attract cells to the site of bone induction. It was suggested that OSF-2 can be applied in metabolic bone diseases (see, for example, EP562508-A). WO0252006-A1 describes OSF-2 as one of several allergy-associated genes inducible by stimulation of airway epithelia cells with interleukin-4 or 13 and the application suggests examining allergic diseases (such as bronchial asthma) by changes in expression levels of the allergy-associated genes. Patent application WO0157062-A1 describes methods for diagnosing inflammatory and renal diseases, such as immunoglobulin A nephropathy, by measuring the levels of OSF-2 in nucleic acid or cell samples from patients.

Dgk epsilon, synaptojanin, G alpha 49B, CG13609, Rab8, Delta, Nup214, Malvolio, or Fasciclin 1 homologous proteins and nucleic acid molecules coding therefore are obtainable from insect or vertebrate species, e.g. mammals or birds. Particularly preferred are homologous nucleic acids, particularly nucleic acids encoding a human protein as described in Table 1 .

The invention particularly relates to a nucleic acid molecule encoding a polypeptide contributing to regulating the energy homeostasis and the metabolism of triglycerides, wherein said nucleic acid molecule comprises

(a) the nucleotide sequence encoding Dgk epsilon, synaptojanin, G alpha 49B, CG13609, Rab8, Delta, Nup214, Malvolio, or Fasciclin 1 or homologous nucleic acids, particularly nucleic acids encoding a human protein as described in Table 1 , and/or a sequence complementary thereto,

(b) a nucleotide sequence which hybridizes at 50°C in a solution containing 1 x SSC and 0.1 % SDS to a sequence of (a),

(c) a sequence corresponding to the sequences of (a) or (b) within the degeneration of the genetic code, (d) a sequence which encodes a polypeptide which is at least 85%, preferably at least 90%, more preferably at least 95%, more preferably at least 98% and up to 99,6% identical to the amino acid sequences of Dgk epsilon, synaptojanin, G alpha 49B, CG 13609, Rab8, Delta, Nup214, Malvolio, or Fasciclinl protein, preferably of the human homologous nucleic acids, particularly nucleic acids encoding a human protein as described in Table 1 , (e) a sequence which differs from the nucleic acid molecule of (a) to (d) by mutation and wherein said mutation causes an alteration, deletion, duplication and/or premature stop in the encoded polypeptide or (f) a partial sequence of any of the nucleotide sequences of (a) to (e) having a length of 15-25 bases, preferably 25-35 bases, more preferably 35-50 bases and most preferably at least 50 bases.

The invention is based on the finding that Dgk epsilon, synaptojanin, G alpha 49B, CG13609, Rab8, Delta, Nup214, Malvolio, or Fasciclinl and/or homologous proteins and the polynucleotides encoding these, are involved in the regulation of triglyceride storage and therefore energy homeostasis. The invention describes the use of these compositions for the diagnosis, study, prevention, or treatment of metabolic diseases or dysfunctions, including metabolic syndrome, obesity, and/or diabetes, as well as related disorders such as eating disorder, cachexia, hypertension, coronary heart disease, hypercholesterolemia, dyslipidemia, osteoarthritis, liver fibrosis, or gallstones.

Accordingly, the present invention relates to genes with novel functions in body-weight regulation, energy homeostasis, metabolism, and obesity, functional fragments of said genes, polypeptides encoded by said genes or functional fragments thereof, and modulators/effectors thereof, e.g. antibodies, biologically active nucleic acids, such as antisense molecules, RNAi molecules, or ribozymes, aptamers, peptides, or low-molecular weight organic compounds recognizing said polynucleotides or polypeptides. The ability to manipulate and screen the genomes of model organisms such as the fly Drosophila melanogaster provides a powerful tool to analyze biological and biochemical processes that have direct relevance to more complex vertebrate organisms due to significant evolutionary conservation of genes, cellular processes, and pathways (see, for example, Adams M. D. et al., (2000) Science 287: 2185-2195). Identification of novel gene functions in model organisms can directly contribute to the elucidation of correlative pathways in mammals (humans) and of methods of modulating them. A correlation between a pathology model (such as changes in triglyceride levels as indication for metabolic syndrome including obesity) and the modified expression of a fly gene can identify the association of the human ortholog with the particular human disease.

In one embodiment, a forward genetic screen is performed in fly displaying a mutant phenotype due to misexpression of a known gene (see, Johnston Nat Rev Genet 3: 176-188 (2002); Rorth P., (1996) Proc Natl Acad Sci U S A 93: 12418-12422). In this invention, we have used a genetic screen to identify mutations that cause changes in the body weight, which are reflected by a significant change of triglyceride levels.

Obese people mainly show a significant increase in the content of triglycerides. Triglycerides are the most efficient storage for energy in cells. In order to isolate genes with a function in energy homeostasis, several thousand proprietary and publicly available EP-lines were tested for their triglyceride content after a prolonged feeding period (see Examples and FIGURES for more detail). Lines with significantly changed triglyceride content were selected as positive candidates for further analysis. The increase or decrease of triglyceride content due to the loss of a gene function suggests gene activities in energy homeostasis in a dose dependent manner that controls the amount of energy stored as triglycerides. ln this invention, the content of triglycerides of a pool of flies with the same genotype was analyzed after prolonged feeding using a triglyceride assay. Male flies homozygous or heterozygous for the integration of vectors for Drosophila EP-lines were analyzed in an assay measuring the triglyceride contents of these flies, illustrated in more detail in the Examples section. The results of the triglyceride content analysis are shown in Figures 1 , 5, 10, 14, 18, 21 , 25, 28, and 32.

Genomic DNA sequences were isolated that are localized adjacent to the EP vector integration. Using those isolated genomic sequences public databases like Berkeley Drosophila Genome Project (GadFly; see also FlyBase (1999) Nucleic Acids Research 27:85-88) were screened thereby identifying the integration site of the vectors, and the corresponding genes, described in more detail in the Examples section. The molecular organization of the genes is shown in Figures 2, 6, 1 1 , 15, 19, 22, 26, 29, and 33.

An additional screen using Drosophila mutants with modifications of the eye phenotype identified an interaction of synaptojanin with adipose, a protein regulating, causing or contributing to obesity. These findings suggest the presence of similar activities of these described homologous proteins in humans that provides insight into diagnosis, treatment, and prognosis of metabolic disorders.

The Drosophila genes and proteins encoded thereby with functions in the regulation of triglyceride metabolism were further analysed in publicly available sequence databases (see Examples for more detail) and mammalian homologs were identified.

The function of the mammalian homologs in energy homeostasis was further validated in this invention by analyzing the expression of the transcripts in different tissues and by analyzing the role in adipocyte differentiation. Expression profiling studies (see Examples for more detail) confirm the particular relevance of the protein(s) of the invention as regulators of energy metabolism in mammals. Further, we show that the proteins of the invention are regulated by fasting and by genetically induced obesity. In this invention, we used mouse models of insulin resistance and/or diabetes, such as mice carrying gene knockouts in the leptin pathway (for example, ob (leptin) or db (leptin receptor) mice) to study the expression of the protein of the invention. Such mice develop typical symptoms of diabetes, show hepatic lipid accumulation and frequently have increased plasma lipid levels (see Bruning et al, 1998, Mol. Cell. 2:449-569).

Microarrays are analytical tools routinely used in bioanalysis. A microarray has molecules distributed over, and stably associated with, the surface of a solid support. The term "microarray" refers to an arrangement of a plurality of polynucleotides, polypeptides, antibodies, or other chemical compounds on a substrate. Microarrays of polypeptides, polynucleotides, and/or antibodies have been developed and find use in a variety of applications, such as monitoring gene expression, drug discovery, gene sequencing, gene mapping, bacterial identification, and combinatorial chemistry. One area in particular in which microarrays find use is in gene expression analysis (see Example 6). Array technology can be used to explore the expression of a single polymorphic gene or the expression profile of a large number of related or unrelated genes. When the expression of a single gene is examined, arrays are employed to detect the expression of a specific gene or its variants. When an expression profile is examined, arrays provide a platform for identifying genes that are tissue specific, are affected by a substance being tested in a toxicology assay, are part of a signaling cascade, carry out housekeeping functions, or are specifically related to a particular genetic predisposition, condition, disease, or disorder. Microarrays may be prepared, used, and analyzed using methods known in the art (see for example, Brennan, T.M. et al. (1995) U.S. Patent No. 5,474,796- Schena, M. et al. (1996) Proc. Natl. Acad. Sci. USA 93: 10614-10619; Baldeschweiler et al. (1995) PCT application WO95/251 1 16; Shalon, D. et al. (1995) PCT application WO95/35505; Heller, R.A. et al. (1997) Proc. Natl. Acad. Sci. USA 94:21502155; Heller, M.J. et al. (1997) U.S. Patent No. 5,605,662). Various types of microarrays are well known and thoroughly described in Schena, M., ed. (1999; DNA Microarrays: A Practical Approach, Oxford University Press, London).

In further embodiments, oligonucleotides or longer fragments derived from any of the polynucleotides described herein may be used as elements on a microarray. The microarray can be used in transcript imaging techniques, which monitor the relative expression levels of large numbers of genes simultaneously as described below. The microarray may also be used to identify genetic variants, mutations, and polymorphisms. This information may be used to determine gene function, to understand the genetic basis of a disorder, to diagnose a disorder, to monitor progression/regression of disease as a function of gene expression, and to develop and monitor the activities of therapeutic agents in the treatment of disease. In particular, this information may be used to develop a pharmacogenomic profile of a patient in order to select the most appropriate and effective treatment regimen for that patient. For example, therapeutic agents, which are highly effective and display the fewest side effects may be selected for a patient based on his/her pharmacogenomic profile.

As determined by Microarray analysis, the human synaptojanin homologs (SYNJ1 , SYNJ2), and the fasciclin 1 -homolog protein OSF-2 show differential expression in human primary adipocytes. Thus, human synaptojanin 1 (SYNJ1 ), synaptojanin 1 (SYNJ2), and the osteoblast specific factor-2 (OSF-2) are strong candidates for the manufacture of a pharmaceutical composition and a medicament for the treatment of conditions related to human metabolism, such as obesity, diabetes, and/or metabolic syndrome.

The invention also encompasses polynucleotides that encode a protein of the invention or a homologous protein. Accordingly, any nucleic acid sequence, which encodes the amino acid sequences of a protein of the invention or a homologous protein, can be used to generate recombinant molecules that express a protein of the invention or a homologous protein. In a particular embodiment, the invention encompasses a nucleic acid encoding Drosophila Dgk epsilon, synaptojanin, G alpha 49B, CG 13609, Rab8, Delta, Nup214, Malvolio, or Fasciclinl or human Dgk epsilon, synaptojanin, G alpha 49B, CG13609, Rab8, Delta, Nup214, Malvolio, or Fasciclinl homologs; referred to as the proteins of the invention. It will be appreciated by those skilled in the art that as a result of the degeneracy of the genetic code, a multitude of nucleotide sequences encoding the proteins, some bearing minimal homology to the nucleotide sequences of any known and naturally occurring gene, may be produced. The invention contemplates each and every possible variation of nucleotide sequence that can be made by selecting combinations based on possible codon choices.

Also encompassed by the invention are polynucleotide sequences that are capable of hybridizing to the claimed nucleotide sequences, and in particular, those of the polynucleotide encoding Dgk epsilon, synaptojanin, G alpha 49B, CG13609, Rab8, Delta, Nup214, Malvolio, or Fasciclinl , or a homologous protein, preferably a human homologous protein as described in Table 1 , under various conditions of stringency. Hybridization conditions are based on the melting temperature (Tm) of the nucleic acid binding complex or probe, as taught in Wahl, G. M. and S. L. Berger (1987: Methods Enzymol. 152:399-407) and Kimmel, A. R. (1987; Methods Enzymol. 152:507-51 1 ), and may be used at a defined stringency. Preferably, hybridization under stringent conditions means that after washing for 1 h with 1 x SSC and 0.1 % SDS at 50 °C, preferably at 55°C, more preferably at 62°C and most preferably at 68°C, particularly for 1 h in 0.2 x SSC and 0.1 % SDS at 50°C, preferably at 55°C, more preferably at 62 °C and most preferably at 68 °C, a positive hybridization signal is observed. Altered nucleic acid sequences encoding the proteins which are encompassed by the invention include deletions, insertions or substitutions of different nucleotides resulting in a polynucleotide that encodes the same or a functionally equivalent protein.

The encoded proteins may also contain deletions, insertions or substitutions of amino acid residues, which produce a silent change and result in functionally equivalent proteins. Deliberate amino acid substitutions may be made on the basis of similarity in polarity, charge, solubility, hydrophobicity, hydrophilicity, and/or the amphipathic nature of the residues as long as the biological activity of the protein is retained. Furthermore, the invention relates to peptide fragments of the proteins or derivatives thereof such as cyclic peptides, retro-inverso peptides or peptide mimetics having a lengh of at least 4, preferably at least 6 and up to 50 amino acids.

Also included within the scope of the present invention are alleles of the genes encoding a protein of the invention or a homologous protein. As used herein, an 'allele' or 'allelic sequence' is an alternative form of the gene, which may result from at least one mutation in the nucleic acid sequence. Alleles may result in altered mRNAs or polypeptides whose structures or function may or may not be altered. Any given gene may have none, one or many allelic forms. Common mutational changes, which give rise to alleles, are generally ascribed to natural deletions, additions or substitutions of nucleotides. Each of these types of changes may occur alone or in combination with the others, one or more times in a given sequence. The nucleic acid sequences encoding a protein of the invention or a homologous protein may be extended utilizing a partial nucleotide sequence and employing various methods known in the art to detect upstream sequences such as promoters and regulatory elements. For example, one method which may be employed, 'restriction-site' PCR, uses universal primers to retrieve unknown sequence adjacent to a known locus (Sarkar, G. (1993) PCR Methods Applic. 2:318-322). Inverse PCR may also be used to amplify or extend sequences using divergent primers based on a known region (Triglia, T. et al. (1988) Nucleic Acids Res. 16:8186). Another method which may be used is capture PCR which involves PCR amplification of DNA fragments adjacent to a known sequence in human and yeast artificial chromosome DNA (Lagerstrom, M. et al. (PCR Methods Applic. 1 : 1 1 1 -1 19). Another method which may be used to retrieve unknown sequences is that of Parker, J. D. et al. (1991 ; Nucleic Acids Res. 19:3055-3060). Additionally, one may use PCR, nested primers, and PROMOTERFINDER libraries to walk in genomic DNA (Clontech, Palo Alto, Calif.). This process avoids the need to screen libraries and is useful in finding intron/exon junctions.

In order to express a biologically active protein, the nucleotide sequences encoding the proteins or functional equivalents, may be inserted into appropriate expression vectors, i.e., a vector which contains the necessary elements for the transcription and translation of the inserted coding sequence. Methods, which are well known to those skilled in the art, may be used to construct expression vectors containing sequences encoding the proteins and the appropriate transcriptional and translational control elements. These methods include in vitro recombinant DNA techniques, synthetic techniques, and in vivo genetic recombination. Such techniques are described in Sambrook, J. et al. (1989) Molecular Cloning, A Laboratory Manual, Cold Spring Harbor Press, Plainview, N.Y. and Ausubel, F.M. et al. (1989) Current Protocols in Molecular Biology, John Wiley & Sons, New York, N.Y. ln a further embodiment of the invention, nucleic acid sequences encoding the sequences of the invention may be ligated to a heterologous sequence to encode a fusion protein. Heterologous sequences are preferably located at the N-and/or C-terminus of the fusion protein.

A variety of expression vector/host systems may be utilized to contain and express sequences encoding the proteins or fusion proteins. These include, but are not limited to, micro-organisms such as bacteria transformed with recombinant bacteriophage, plasmid or cosmid DNA expression vectors; yeast transformed with yeast expression vectors; insect cell systems infected with virus expression vectors (e.g., baculovirus); plant cell systems transformed with virus expression vectors (e.g., cauliflower mosaic virus, CaMV; tobacco mosaic virus, TMV) or with bacterial expression vectors (e.g., Ti or PBR322 plasmids); or animal cell systems.

The presence of polynucleotide sequences encoding a protein of the invention or a homologous protein can be detected by DNA-DNA or DNA-RNA hybridization and/or amplification using probes or portions or fragments of said polynucleotides encoding a protein of the invention or a homologous protein. Nucleic acid amplification based assays involve the use of oligonucleotides or oligomers based on the sequences specific for the gene to detect transformants containing DNA or RNA encoding the corresponding protein. As used herein 'oligonucleotides' or 'oligomers' refer to a nucleic acid sequence of at least about 10 nucleotides and as many as about 60 nucleotides, preferably about 15 to 30 nucleotides, and more preferably about 20-25 nucleotides, which can be used as a probe or amplimer.

A variety of protocols for detecting and measuring the expression of proteins, using either polyclonal or monoclonal antibodies specific for the protein are known in the art. Examples include enzyme-linked immunosorbent assay (ELISA), radioimmunoassay (RIA), and fluorescence activated cell sorting (FACS). A two-site, monoclonal-based immunoassay utilizing monoclonal antibodies reactive to two non-interfering epitopes on the protein is preferred, but a competitive binding assay may be employed. These and other assays are described, among other places, in Hampton, R. et al. (1990; Serological Methods, a Laboratory Manual, APS Press, St Paul, Minn.) and Maddox, D. E. et al. (1983; J. Exp. Med. 158:121 1 -1216).

A wide variety of labels and conjugation techniques are known by those skilled in the art and may be used in various nucleic acid and protein, e.g. immunological assays. Means for producing labeled hybridization or PCR probes for detecting polynucleotides encoding a protein of the invention or a homologous protein include oligo-labeling, nick translation, end-labeling of RNA probes, PCR amplification using a labeled nucleotide, or enzymatic synthesis. These procedures may be conducted using a variety of commercially available kits (Pharmacia & Upjohn, (Kalamazoo, Mich.); Promega (Madison Wis.); and U.S. Biochemical Corp., (Cleveland, Ohio).

Suitable reporter molecules or labels, which may be used for nucleic acid and protein assays, include radionuclides, enzymes, fluorescent, chemiluminescent or chromogenic agents as well as substrates, co-factors, inhibitors, magnetic particles, and the like.

Host cells transformed with nucleotide sequences encoding the protein may be cultured under conditions suitable for the expression and recovery of the protein from cell culture. The protein produced by a recombinant cell may be secreted or contained intracellularly depending on the sequence and/or the vector used. As will be understood by those of skill in the art, expression vectors containing polynucleotides which encode the protein may be designed to contain signal sequences, which direct secretion of the protein through a prokaryotic or eukaryotic cell membrane. Other recombinant constructions may be used to join sequences encoding the protein to nucleotide sequence encoding a polypeptide domain, which will facilitate purification of soluble proteins. Such purification facilitating domains include, but are not limited to, metal chelating peptides such as histidine-tryptophan modules that allow purification on immobilized metals, protein A domains that allow purification on immobilized immunoglobulin, and the domain utilized in the FLAG extension/affinity purification system (Immunex Corp., Seattle, Wash.) The inclusion of cleavable linker sequences such as those specific for Factor XA or Enterokinase (Invitrogen, San Diego, Calif.) between the purification domain and the desired protein may be used to facilitate purification.

Diagnostics and Therapeutics

The data disclosed in this invention show that the nucleic acids and proteins of the invention and effectors/modulators thereof are useful in diagnostic and therapeutic applications implicated, for example but not limited to, in metabolic diseases or dysfunctions, including metabolic syndrome, obesity, and/or diabetes as well as related disorders such as eating disorder, cachexia, hypertension, coronary heart disease, hypercholesterolemia, dyslipidemia, osteoarthritis, or gallstones. Hence, diagnostic and therapeutic uses for the nucleic acids and proteins of the invention are, for example but not limited to, the following: (i) protein therapy, (ii) small molecule drug target, (iii) antibody target (therapeutic, diagnostic, drug targeting/cytotoxic antibody), (iv) diagnostic and/or prognostic marker, (v) gene therapy (gene delivery/gene ablation), (vi) research tools, and (vii) tissue regeneration in vitro and in vivo (regeneration for all these tissues and cell types composing these tissues and cell types derived from these tissues).

The nucleic acids and proteins of the invention and modulators/effectors thereof are useful in diagnostic and therapeutic applications implicated in various applications as described below. For example, but not limited to, cDNAs encoding the proteins of the invention and particularly their human homologues may be useful in gene therapy, and the proteins of the invention and particularly their human homologues may be useful when administered to a subject in need thereof. By way of non-limiting example, the compositions of the present invention will have efficacy for treatment of patients suffering from, for example, but not limited to, in metabolic disorders as described above.

The nucleic acids encoding a protein of the invention or a homologous protein or a functional fragment thereof, may further be useful in diagnostic applications, wherein the presence or amount of the nucleic acids or the proteins are to be assessed. These materials are further useful in the generation of antibodies that bind immunospecifically to the novel substances of the invention may be used in therapeutic or diagnostic methods.

For example, in one aspect, antibodies, which are specific for a protein of the invention or a homologous protein, may be used directly as a modulator/effector, e.g. an antagonist or indirectly as a targeting or delivery mechanism for bringing a pharmaceutical agent to cells or tissue which express the protein. The antibodies may be generated using methods that are well known in the art. Such antibodies may include, but are not limited to, polyclonal, monoclonal, chimeric single chain, Fab fragments, and fragments produced by a Fab expression library. Neutralising antibodies, (i.e., those which inhibit dimer formation) are especially preferred for therapeutic use.

For the production of antibodies, various hosts including goats, rabbits, rats, mice, humans, and others, may be immunized by injection with the protein or any fragment or oligopeptide thereof which has immunogenic properties. Depending on the host species, various adjuvants may be used to increase immunological response. It is preferred that the peptides, fragments or oligopeptides used to induce antibodies to the protein have an amino acid sequence consisting of at least five amino acids, and more preferably at least 10 amino acids.

Monoclonal antibodies to the proteins may be prepared using any technique that provides for the production of antibody molecules by continuous cell lines in culture. These include, but are not limited to, the hybridoma technique, the human B-cell hybridoma technique, and the EBV-hybridoma technique (Kohler, G. and Milstein C. (1975) Nature 256:495-497; Kozbor, D. et al. (1985) J. Immunol. Methods 81 :31 -42; Cote, R. J. et al. Proc. Natl. Acad. Sci. 80:2026-2030; Cole, S. P. et al. (1984) Mol. Cell Biol. 62:109-120).

In addition, techniques developed for the production of 'chimeric antibodies', the splicing of mouse antibody genes to human antibody genes to obtain a molecule with appropriate antigen specificity and biological activity can be used (Morrison, S. L. et al. (1984) Proc. Natl. Acad. Sci. 81 :6851 -6855; Neuberger, M. S. et al (1984) Nature 312:604-608; Takeda, S. et al. (1985) Nature 314:452-454). Alternatively, techniques described for the production of single chain antibodies may be adapted, using methods known in the art, to produce single chain antibodies specific for a protein of the invention or a homologous protein. Antibodies with related specificity, but of distinct idiotypic composition, may be generated by chain shuffling from random combinatorial immunoglobulin libraries (Burton, D. R. (1991 ) Proc. Natl. Acad. Sci. 88:1 1 120-3). Antibodies may also be produced by inducing in vivo production in the lymphocyte population or by screening recombinant immunoglobulin libraries or panels of highly specific binding reagents as disclosed in the literature (Orlandi, R. et al. (1 989) Proc. Natl. Acad. Sci. 86:3833-3837; Winter, G. et al. (1991 ) Nature 349:293-299). Antibody fragments which contain specific binding sites for the proteins may also be generated. For example, such fragments include, but are not limited to, the F(ab')₂ fragments which can be produced by Pepsin digestion of the antibody molecule and the Fab fragments which can be generated by reducing the disulfide bridges of F(ab')₂ fragments. Alternatively, Fab expression libraries may be constructed to allow rapid and easy identification of monoclonal Fab fragments with the desired specificity (Huse, W. D. et al. (1989) Science 254:1275-1281 ).

Various immunoassays may be used for screening to identify antibodies having the desired specificity. Numerous protocols for competitive binding and immunoradiometric assays using either polyclonal or monoclonal antibodies with established specificities are well known in the art. Such immunoassays typically involve the measurement of complex formation between the protein and its specific antibody. A two-site, monoclonal-based immunoassay utilizing monoclonal antibodies reacive to two non-interfering protein epitopes are preferred, but a competitive binding assay may also be employed (Maddox, supra).

In another embodiment of the invention, the polynucleotides of the invention or fragments thereof or nucleic acid modulator/effector molecules such as aptamers, antisense molecules, RNAi molecules or ribozymes may be used for therapeutic purposes. In one aspect, aptamers, i.e. nucleic acid molecules, which are capable of binding to a protein of the invention and modulating its activity may be generated by a screening and selection procedure involving the use of combinatorial nucleic acid libraries.

In a further aspect, antisense molecules may be used in situations in which it would be desirable to block the transcription of the mRNA. In particular, cells may be transformed with sequences complementary to polynucleotides encoding a protein of the invention or a homologous protein. Thus, antisense molecules may be used to modulate/effect protein activity or to achieve regulation of gene function. Such technology is now well known in the art, and sense or antisense oligomers or larger fragments, can be designed from various locations along the coding or control regions of sequences encoding the proteins. Expression vectors derived from retroviruses, adenovirus, herpes or vaccinia viruses or from various bacterial plasmids may be used for delivery of nucleotide sequences to the targeted organ, tissue or cell population. Methods, which are well known to those skilled in the art, can be used to construct recombinant vectors, which will express antisense molecules complementary to the polynucleotides of the genes encoding a protein of the invention or a homologous protein. These techniques are described both in Sambrook et al. (supra) and in Ausubel et al. (supra). Genes encoding a protein of the invention or a homologous protein can be turned off by transforming a cell or tissue with expression vectors, which express high levels of polynucleotides that encode a protein of the invention or a homologous protein or a functional fragment thereof. Such constructs may be used to introduce untranslatable sense or antisense sequences into a cell. Even in the absence of integration into the DNA, such vectors may continue to transcribe RNA molecules until they are disabled by endogenous nucleases. Transient expression may last for a month or more with a non-replicating vector and even longer if appropriate replication elements are part of the vector system.

As mentioned above, modifications of gene expression can be obtained by designing antisense molecules, e.g. DNA, RNA or nucleic acid analogues such as PNA, to the control regions of the genes encoding a protein of the invention or a homologous protein, i.e., the promoters, enhancers, and introns. Oligonucleotides derived from the transcription initiation site, e.g., between positions -10 and + 10 from the start site, are preferred. Similarly, inhibition can be achieved using "triple helix" base-pairing methodology. Triple helix pairing is useful because it cause inhibition of the ability of the double helix to open sufficiently for the binding of polymerases, transcription factors or regulatory molecules. Recent therapeutic advances using triplex DNA have been described in the literature (Gee, J. E. et al. (1994) In; Huber, B. E. and B. I. Carr, Molecular and Immunologic Approaches, Futura Publishing Co., Mt. Kisco, N.Y.). The antisense molecules may also be designed to block translation of mRNA by preventing the transcript from binding to ribosomes.

Ribozymes, enzymatic RNA molecules, may also be used to catalyze the specific cleavage of RNA. The mechanism of ribozyme action involves sequence-specific hybridization ofthe ribozyme molecule to complementary target RNA, followed by endonucleolytic cleavage. Examples, which may be used, include engineered hammerhead motif ribozyme molecules that can be specifically and efficiently catalyze endonucleolytic cleavage of sequences encoding a protein of the invention or a homologous protein. Specific ribozyme cleavage sites within any potential RNA target are initially identified by scanning the target molecule for ribozyme cleavage sites which include the following sequences: GUA, GUU, and GUC. Once identified, short RNA sequences of between 15 and 20 ribonucleotides corresponding to the region of the target gene containing the cleavage site may be evaluated for secondary structural features which may render the oligonucleotide inoperable. The suitability of candidate targets may also be evaluated by testing accessibility to hybridization with complementary oligonucleotides using ribonuclease protection assays.

Nucleic acid effector molecules, e.g. antisense molecules and ribozymes of the invention may be prepared by any method known in the art for the synthesis of nucleic acid molecules. These include techniques for chemically synthesizing oligonucleotides such as solid phase phosphoramidite chemical synthesis. Alternatively, RNA molecules may be generated by in vitro and in vivo transcription of DNA sequences encoding a protein of the invention or a homologous protein. Such DNA sequences may be incorporated into a variety of vectors with suitable RNA polymerase promoters such as T7 or SP6. Alternatively, these cDNA constructs that synthesize antisense RNA constitutively or inducibly can be introduced into cell lines, cells or tissues. RNA molecules may be modified to increase intracellular stability and half-life. Possible modifications include, but are not limited to, the addition of flanking sequences at the 5' and/or 3' ends of the molecule or modifications in the nucleobase, sugar and/or phosphate moieties, e.g. the use of phosphorothioate or 2' O-methyl rather than phosphodiesterase linkages within the backbone of the molecule. This concept is inherent in the production of PNAs and can be extended in all of these molecules by the inclusion of non-traditional bases such as inosine, queosine, and wybutosine, as well as acetyl-, methyl-, thio-, and similarly modified forms of adenine, cytidine, guanine, thymine, and uridine which are not as easily recognized by endogenous endonucleases.

Many methods for introducing vectors into cells or tissues are available and equally suitable for use in vivo, in vitro, and ex vivo. For ex vivo therapy, vectors may be introduced into stem cells taken from the patient and clonally propagated for autologous transplant back into that same patient. Delivery by transfection and by liposome injections may be achieved using methods, which are well known in the art. Any of the therapeutic methods described above may be applied to any suitable subject including, for example, mammals such as dogs, cats, cows, horses, rabbits, monkeys, and most preferably, humans.

An additional embodiment of the invention relates to the administration of a pharmaceutical composition, in conjunction with a pharmaceutically acceptable carrier, for any of the therapeutic effects discussed above. Such pharmaceutical compositions may consist of a protein of the invention or a homologous nucleic acid sequence or protein, antibodies to a protein of the invention or a homologous protein, mimetics, agonists, antagonists or inhibitors of a protein of the invention or a homologous protein or nucleic acid sequence. The compositions may be administered alone or in combination with at least one other agent, such as stabilizing compound, which may be administered in any sterile, biocompatible pharmaceutical carrier, including, but not limited to, saline, buffered saline, dextrose, and water. The compositions may be administered to a patient alone or in combination with other agents, drugs or hormones. The pharmaceutical compositions utilized in this invention may be administered by any number of routes including, but not limited to, oral, intravenous, intramuscular, intra-arterial, intramedullary, intrathecal, intraventricular, transdermal, subcutaneous, intraperitoneal, intranasal, enteral, topical, sublingual or rectal means.

In addition to the active ingredients, these pharmaceutical compositions may contain suitable pharmaceutically-acceptable carriers comprising excipients and auxiliaries, which facilitate processing of the active compounds into preparations, which can be used pharmaceutically. Further details on techniques for formulation and administration may be found in the latest edition of Remington's Pharmaceutical Sciences (Maack Publishing Co., Easton, Pa.).

The pharmaceutical compositions of the present invention may be manufactured in a manner that is known in the art, e.g., by means of conventional mixing, dissolving, granulating, dragee-making, levigating, emulsifying, encapsulating, entrapping or lyophilizing processes. The pharmaceutical composition may be provided as a salt and can be formed with many acids. After pharmaceutical compositions have been prepared, they can be placed in an appropriate container and labeled for treatment of an indicated condition. For administration of proteins, such labeling would include amount, frequency, and method of administration.

Pharmaceutical compositions suitable for use in the invention include compositions wherein the active ingredients are contained in an effective amount to achieve the intended purpose. The determination of an effective dose is well within the capability of those skilled in the art. For any compound, the therapeutically effective dose can be estimated initially either in cell culture assays, e.g., of preadipocyte cell lines or in animal models, usually mice, rabbits, dogs or pigs. The animal model may also be used to determine the appropriate concentration range and route of administration. Such information can then be used to determine useful doses and routes for administration in humans. A therapeutically effective dose refers to that amount of active ingredient, for example a protein of the invention or a homologous protein or nucleic acid sequence or functional fragment thereof or an antibody, which is sufficient for treating a specific condition. Therapeutic efficacy and toxicity may be determined by standard pharmaceutical procedures in cell cultures or experimental animals, e.g., ED50 (the dose therapeutically effective in 50% of the population) and LD50 (the dose lethal to 50% of the population). The dose ratio between therapeutic and toxic effects is the therapeutic index, and it can be expressed as the ratio, LD50/ED50. Pharmaceutical compositions, which exhibit large therapeutic indices, are preferred. The data obtained from cell culture assays and animal studies is used in formulating a range of dosage for human use. The dosage contained in such compositions is preferably within a range of circulating concentrations that include the ED50 with little or no toxicity. The dosage varies within this range depending upon the dosage from employed, sensitivity of the patient, and the route of administration. The exact dosage will be determined by the practitioner, in light of factors related to the subject that requires treatment. Dosage and administration are adjusted to provide sufficient levels of the active moiety or to maintain the desired effect. Factors, which may be taken into account, include the severity of the disease state, general health of the subject, age, weight, and gender of the subject, diet, time and frequency of administration, drug combination(s), reaction sensitivities, and tolerance/response to therapy. Long-acting pharmaceutical compositions may be administered every 3 to 4 days, every week or once every two weeks depending on half-life and clearance rate of the particular formulation. Normal dosage amounts may vary from 0.1 to 100,000 micrograms, up to a total dose of about 1 g, depending upon the route of administration. Guidance as to particular dosages and methods of delivery is provided in the literature and generally available to practitioners in the art. Those skilled in the art employ different formulations for nucleotides than for proteins or their inhibitors. Similarly, delivery of polynucleotides or polypeptides will be specific to particular cells, conditions, locations, etc.

In another embodiment, antibodies which specifically bind to a protein of the invention may be used for the diagnosis of conditions or diseases characterized by or associated with over- or underexpression of a protein of the invention or a homologous protein or in assays to monitor patients being treated with a protein of the invention or a homologous protein, or modulators/effectors thereof, e.g. agonists, antagonists or inhibitors. Diagnostic assays include methods which utilize the antibody and a label to detect the protein in human body fluids or extracts of cells or tissues. The antibodies may be used with or without modification, and may be labeled by joining them, either covalently or non-covalently, with a reporter molecule. A wide variety of reporter molecules which are known in the art may be used several of which are described above.

A variety of protocols including ELISA, RIA, and FACS for measuring proteins are known in the art and provide a basis for diagnosing altered or abnormal levels of gene expression. Normal or standard values for gene expression are established by combining body fluids or cell extracts taken from normal mammalian subjects, preferably human, with antibodies to the protein under conditions suitable for complex formation. The amount of standard complex formation may be quantified by various methods, but preferably by photometric means. Quantities of protein expressed in control and disease, samples e.g. from biopsied tissues are compared with the standard values. Deviation between standard and subject values establishes the parameters for diagnosing disease.

In another embodiment of the invention, the polynucleotides specific for a protein of the invention or a homologous protein may be used for diagnostic purposes. The polynucleotides, which may be used, include oligonucleotide sequences, antisense RNA and DNA molecules, and PNAs. The polynucleotides may be used to detect and quantitate gene expression in biopsied tissues in which gene expression may be correlated with disease. The diagnostic assay may be used to distinguish between absence, presence, and excess gene expression, and to monitor regulation of protein levels during therapeutic intervention.

In one aspect, hybridization with probes which are capable of detecting polynucleotide sequences, including genomic sequences, encoding a protein of the invention or a homologous protein or closely related molecules, may be used to identify nucleic acid sequences which encode the respective protein. The hybridization probes of the subject invention may be DNA or RNA and are preferably derived from the nucleotide sequence of the polynucleotide encoding a protein of the invention or a homologous protein or from a genomic sequence including promoter, enhancer elements, and introns of the naturally occurring gene. Means for producing specific hybridization probes for DNAs encoding a protein of the invention or a homologous protein include the cloning of nucleic acid sequences specific for a protein of the invention or a homologous protein into vectors for the production of mRNA probes. Such vectors are known in the art, commercially available, and may be used to synthesize RNA probes in vitro by means of the addition of the appropriate RNA polymerases and the appropriate labeled nucleotides. Hybridization probes may be labeled by a variety of reporter groups, for example, radionuclides such as ³²P or ³⁵S or enzymatic labels, such as alkaline phosphatase coupled to the probe via avidin/biotin coupling systems, and the like. Polynucleotide sequences specific for a protein of the invention or homologous nucleic nucleic acids may be used for the diagnosis of conditions or diseases, which are associated with the expression of the proteins. Examples of such conditions or diseases include, but are not limited to, metabolic diseases and disorders, including obesity and diabetes. Polynucleotide sequences specific for a protein of the invention or a homologous protein may also be used to monitor the progress of patients receiving treatment for metabolic diseases and disorders, including obesity and diabetes. The polynucleotide sequences may be used qualitative or quantitative assays, e.g. in Southern or Northern analysis, dot blot or other membrane-based technologies; in PCR technologies; or in dip stick, pin, ELISA or chip assays utilizing fluids or tissues from patient biopsies to detect altered gene expression. Such qualitative or quantitative methods are well known in the art.

In a particular aspect, the nucleotide sequences specific for a protein of the invention or homologous nucleic acids may be useful in assays that detect activation or induction of various metabolic diseases or dysfunctions, including metabolic syndrome, obesity, and/or diabetes as well as related disorders such as eating disorder, cachexia, hypertension, coronary heart disease, hypercholesterolemia, dyslipidemia, osteoarthritis, or gallstones. The nucleotide sequences may be labeled by standard methods, and added to a fluid or tissue sample from a patient under conditions suitable for the formation of hybridization complexes. After a suitable incubation period, the sample is washed and the signal is quantitated and compared with a standard value. The presence of altered levels of nucleotide sequences encoding a protein of the invention or a homologous protein in the sample indicates the presence of the associated disease. Such assays may also be used to evaluate the efficacy of a particular therapeutic treatment regimen in animal studies, in clinical trials or in monitoring the treatment of an individual patient. In order to provide a basis for the diagnosis of a disease associated with expression of a protein of the invention or a homologous protein, a normal or standard profile for expression is established. This may be accomplished by combining body fluids or cell extracts taken from normal subjects, either animal or human, with a sequence or a fragment thereof, which is specific for the nucleic acids encoding a protein of the invention or homologous nucleic acids, under conditions suitable for hybridization or amplification. Standard hybridization may be quantified by comparing the values obtained from normal subjects with those from an experiment where a known amount of a substantially purified polynucleotide is used. Standard values obtained from normal samples may be compared with values obtained from samples from patients who are symptomatic for disease. Deviation between standard and subject values is used to establish the presence of disease. Once disease is established and a treatment protocol is initiated, hybridization assays may be repeated on a regular basis to evaluate whether the level of expression in the patient begins to approximate that, which is observed in the normal patient. The results obtained from successive assays may be used to show the efficacy of treatment over a period ranging from several days to months.

With respect to metabolic diseases or dysfunctions, including metabolic syndrome, obesity, and/or diabetes, the presence of a relatively high amount of transcript in biopsied tissue from an individual may indicate a predisposition for the development of the disease or may provide a means for detecting the disease prior to the appearance of actual clinical symptoms. A more definitive diagnosis of this type may allow health professionals to employ preventative measures or aggressive treatment earlier thereby preventing the development or further progression of the metabolic diseases or dysfunctions. Additional diagnostic uses for oligonucleotides designed from the sequences encoding a protein of the invention or a homologous protein may involve the use of PCR. Such oligomers may be chemically synthesized, generated enzymatically or produced from a recombinant source. Oligomers will preferably consist of two nucleotide sequences, one with sense orientation (5'.fwdarw.3') and another with antisense (3'.rarw.5'), employed under optimized conditions for identification of a specific gene or condition. The same two oligomers, nested sets of oligomers or even a degenerate pool of oligomers may be employed under less stringent conditions for detection and/or quantification of closely related DNA or RNA sequences.

Methods which may also be used to quantitate the expression of a protein of the invention or a homologous protein include radiolabeling or biotinylating nucleotides, coamplification of a control nucleic acid, and standard curves onto which the experimental results are interpolated (Melby, P. C. et al. (1993) J. Immunol. Methods, 159:235-244; Duplaa, C. et al. (1993) Anal. Biochem. 212:229-236). The speed of quantification of multiple samples may be accelerated by running the assay in an ELISA format where the oligomer of interest is presented in various dilutions and a spectrophotometric or colorimetric response gives rapid quantification.

In another embodiment of the invention, the nucleic acid sequences which are specific for a protein of the invention or homologous nucleic acids may also be used to generate hybridization probes, which are useful for mapping the naturally occurring genomic sequence. The sequences may be mapped to a particular chromosome or to a specific region of the chromosome using well known techniques. Such techniques include FISH, FACS or artificial chromosome constructions, such as yeast artificial chromosomes, bacterial artificial chromosomes, bacterial P1 constructions or single chromosome cDNA libraries as reviewed in Price, C. M. (1993)

Blood Rev. 7:127-134, and Trask, B. J. (1991 ) Trends Genet. 7:149-154.

FISH (as described in Verma et al. (1 988) Human Chromosomes: A Manual of Basic Techniques, Pergamon Press, New York, N.Y.). The results may be correlated with other physical chromosome mapping techniques and genetic map data. Examples of genetic map data can be found in the 1994 Genome Issue of Science (265: 1981 f). Correlation between the location of the gene encoding a protein of the invention or a homologous proteinon a physical chromosomal map and a specific disease or predisposition to a specific disease, may help to delimit the region of DNA associated with that genetic disease.

The nucleotide sequences of the subject invention may be used to detect differences in gene sequences between normal, carrier, or affected individuals. An analysis of polymorphisms, e.g. single nucleotide polymorphisms may be carried out. Further, in situ hybridisation of chromosomal preparations and physical mapping techniques such as linkage analysis using established chromosomal markers may be used for extending genetic maps. Often the placement of a gene on the chromosome of another mammalian species, such as mouse, may reveal associated markers even if the number or arm of a particular human chromosome is not known. New sequences can be assigned to chromosomal arms, or parts thereof, by physical mapping. This provides valuable information to investigators searching for disease genes using positional cloning or other gene discovery techniques. Once the disease or syndrome has been crudely localised by genetic linkage to a particular genomic region, for example, AT to 1 1 q22-23 (Gatti, R. A. et al. (1988) Nature 336:577-580), any sequences mapping to that area may represent associated or regulatory genes for further investigation. The nucleotide sequences of the subject invention may also be used to detect differences in the chromosomal location due to translocation, inversion, etc. among normal, carrier, or affected individuals.

In another embodiment of the invention, the proteins of the invention, their catalytic or immunogenic fragments or oligopeptides thereof, an in vitro model, a genetically altered cell or animal, can be used for screening libraries of compounds, e.g. peptides or low molecular weight organic compounds, in any of a variety of drug screening techniques. One can identify modulators/effectors, e.g. receptors, enzymes, proteins, ligands, or substrates that bind to, modulate or mimic the action of one or more of the proteins of the invention. The protein or fragment thereof employed in such screening may be free in solution, affixed to a solid support, borne on a cell surface, or located intracellularly. The formation of binding complexes, between the protein and the agent tested, may be measured. Agents could also, either directly or indirectly, influence the activity of the proteins of the invention.

In vivo, the enzymatic kinase activity of the unmodified polypeptides of diacylglycerol kinase, epsilon 64kDa (DGKE), or homologues thereof towards a substrate can be measured. Activation of the kinase may be induced in the natural context by extracellular or intracellular stimuli, such as signaling molecules or environmental influences. One may generate a system containing DGKE, or homologues thereof, may it be an organism, a tissue, a culture of cells or cell-free environment, by exogenously applying this stimulus or by mimicking this stimulus by a variety of the techniques, some of them described further below. A system containing activated DGKE, or homologues thereof may be produced (i) for the purpose of diagnosis, study, prevention, and treatment of diseases and disorders related to body-weight regulation and thermogenesis, for example, but not limited to, metabolic diseases, (ii) for the purpose of identifying or validating therapeutic candidate agents, pharmaceuticals or drugs that influence the genes of the invention or their encoded polypeptides, (iii) for the purpose of generating cell lysates containing activated polypeptides encoded by the genes of the invention, (iv) for the purpose of isolating from this source activated polypeptides encoded by the genes of the invention.

In one embodiment of the invention, one may produce activated DGKE independent of the natural stimuli for the above said purposes by, for example, but not limited to, (i) an agent that mimics the natural stimulus; (ii) an agent, that acts downstream of the natural stimulus, such as activators of DGKE, constitutive active alleles of DGKE itself as they are described or may be developed; (iii) by introduction of single or multiple amino acid substitutions, deletions or insertions within the sequence of DGKE to yield constitutive active forms; (iv) by the use of isolated fragments of DGKE. In addition, one may generate enzymatically active DGKE in an ectopic system, prokaryotic or eukaryotic, in vivo or in vitro, by co-transfering to this system the activating components.

In addition activity of Dgk epsilon, synaptojanin, G alpha 49B, CG13609, Rab8, Delta, Nup214, Malvolio, or Fasciclin 1 or homologous proteins against their physiological substrate(s) or derivatives thereof could be measured in cell-based assays. Agents may also interfere with posttranslational modifications of the proteins of the invention, such as phosphorylation and dephosphorylation, famesylation, palmitoylation, acetylation, alkylation, ubiquitination, proteolytic processing, subcellular localization and degradation. Moreover, agents could influence the dimerization or oligomerization of the proteins of the invention or, in a heterologous manner, of the proteins of the invention with other proteins, for example, but not exclusively, docking proteins, enzymes, receptors, ion channels, uncoupling proteins, or translation factors. Agents could also act on the physical interaction of the proteins of this invention with other proteins, which are required for protein function, for example, but not exclusively, their downstream signaling.

Methods for determining protein-protein interaction are well known in the art. For example binding of a fluorescently labeled peptide derived from a protein of the invention to the interacting protein (or vice versa) could be detected by a change in polarisation. In case that both binding partners, which can be either the full length proteins as well as one binding partner as the full length protein and the other just represented as a peptide are fluorescently labeled, binding could be detected by fluorescence energy transfer (FRET) from one fluorophore to the other. In addition, a variety of commercially available assay principles suitable for detection of protein-protein interaction are well known In the art, for example but not exclusively AlphaScreen (PerkinElmer) or Scintillation Proximity Assays (SPA) by Amersham. Alternatively, the interaction of the proteins of the invention with cellular proteins could be the basis for a cell-based screening assay, in which both proteins are fluorescently labeled and interaction of both proteins is detected by analysing cotranslocation of both proteins with a cellular imaging reader, as has been developed for example, but not exclusively, by Cellomics or EvotecOAI. In all cases the two or more binding partners can be different proteins with one being the protein of the invention, or in case of dimerization and/or oligomerization the protein of the invention itself. Proteins of the invention, for which one target mechanism of interest, but not the only one, would be such protein/protein interactions are Dgk epsilon, synaptojanin, G alpha 49B, CG 13609, Rab8, Delta, Nup214, Malvolio, or Fasciclin 1 or homologous proteins.

Assays for determining enzymatic, carrier, or ion channel activity of the proteins of the invention are well known in the art. Well known in the art are also a variety of assay formats to measure receptor-ligand binding.

The phosphatase activity of a protein of the invention could be measured in vitro by using recombinantly expressed and purified synaptojanin or fragments thereof by making use of artificial phosphatase substrates well known in the art, i.e. but not exclusively DiFMUP or FDP (Molecular Probes, Eugene, Oregon), which are converted to fluorophores or chromophores upon dephosphorylation . Alternatively, the dephosphorylation of physiological substrates of synaptojanin could be measured by making use of any of the well known screening technologies suitable for the detection of the phosphorylation status of synaptojanin inositol and phosphatidylinositol substrates, i.e. in a procedure similar as described for the inositol phosphatase SHIP2 (T. Habib et al. (1998), JBC 273, 18605-18609). In addition activity of synaptojanin against its physiological substrate(s) or derivatives thereof could be measured in cell-based assays, thereby determining activity of the phosphatase at the level of their downstream signalling.

Of particular interest are screening assays for agents that have a low toxicity for mammalian cells. The term "agent" as used herein describes any molecule, e.g. protein or pharmaceutical, with the capability of altering or mimicking the physiological function of one or more of the proteins of the invention. Candidate agents encompass numerous chemical classes, though typically they are organic molecules, preferably small organic compounds having a molecular weight of more than 50 and less than about 2,500 Daltons. Candidate agents comprise functional groups necessary for structural interaction with proteins, particularly hydrogen bonding, and typically include at least an amine, carbonyl, hydroxyl or carboxyl group, preferably at least two of the functional chemical groups. The candidate agents often comprise carbocyclic or heterocyclic structures and/or aromatic or polyaromatic structures substituted with one or more of the above functional groups.

Candidate agents are also found among biomolecules including peptides, saccharides, fatty acids, steroids, purines, pyrimidines, nucleic acids and derivatives, structural analogs or combinations thereof. Candidate agents are obtained from a wide variety of sources including libraries of synthetic or natural compounds. For example, numerous means are available for random and directed synthesis of a wide variety of organic compounds and biomolecules, including expression of randomized oligonucleotides and oligopeptides. Alternatively, libraries of natural compounds in the form of bacterial, fungal, plant and animal extracts are available or readily produced. Additionally, natural or synthetically produced libraries and compounds are readily modified through conventional chemical, physical and biochemical means, and may be used to produce combinatorial libraries. Known pharmacological agents may be subjected to directed or random chemical modifications, such as acylation, alkylation, esterification, amidification, etc. to produce structural analogs. Where the screening assay is a binding assay, one or more of the molecules may be joined to a label, where the label can directly or indirectly provide a detectable signal.

Candidate agents may also be found in kinase assays where a kinase substrate such as a protein, a peptide, a lipid, or an organic compound, which may or may not include modifications as further described below, or others are phosphorylated by the proteins or protein fragments of the invention. The kinase can be a protein of the invention (e.g. DGKE) or a kinase which is influenced in its activity by a protein of the invention (e.g. mel transforming oncogene (derived from cell line NK14)- RAB8 homolog (MEL), or RAB-8b protein (LOC51762)). A therapeutic candidate agent may be identified by its ability to increase or decrease the enzymatic activity of the proteins of the invention. The kinase activity may be detected by change of the chemical, physical or immunological properties of the substrate due to phosphorylation. One example could be the transfer of radioisotopically labelled phosphate groups from an appropriate donor molecule to the kinase substrate catalyzed by the polypeptides of the invention. The phosphorylation of the substrate may be followed by detection of the substrates autoradiography with techniques well known in the art.

Yet in another example, the change of mass of the substrate due to its phosphorylation may be detected by mass spectrometry techniques. One could also detect the phosphorylation status of a substrate with an analyte discriminating between the phosphorylated and unphosphorylated status of the substrate. Such an analyte may act by having different affinities for the phosphorylated and unphosphorylated forms of the substrate or by having specific affinity for phosphate groups. Such an analyte could be, but is not limited to, an antibody or antibody derivative, a recombinant antibody-like structure, a protein, a nucleic acid, a molecule containing a complexed metal ion, an anion exchange chromatography matrix, an affinity chromatography matrix or any other molecule with phosphorylation dependend selectivity towards the substrate.

Such an analyte could be employed to detect the kinase substrate, which is immobilized on a solid support during or after an enzymatic reaction. If the analyte is an antibody, its binding to the substrate could be detected by a variety of techniques as they are described in Harlow and Lane, 1998, Antibodies, CSH Lab Press, NY. If the analyte molecule is not an antibody, it may be detected by virtue of its chemical, physical or immunological properties, being endogenously associated with it or engineered to it.

Yet in another example the kinase substrate may have features, designed or endogenous, to facilitate its binding or detection in order to generate a signal that is suitable for the analysis of the substrates phosphorylation status. These features may be, but are not limited to, a biotin molecule or derivative thereof, a glutathione-S-transferase moiety, a moiety of six or more consecutive histidine residues, an amino acid sequence or hapten to function as an epitope tag, a fluorochrome, an enzyme or enzyme fragment. The kinase substrate may be linked to these or other features with a molecular spacer arm to avoid steric hindrance.

In one example, the kinase substrate may be labelled with a fluorochrome. The binding of the analyte to the labelled substrate in solution may be followed by the technique of fluorescence polarization as it is described in the literature (see, for example, Deshpande, S. et al. (1999) Prog. Biomed.

Optics (SPIE) 3603:261 ; Parker, G. J. et al. (2000) J. Biomol. Screen.

5:77-88; Wu, P. et al. (1997) Anal. Biochem. 249:29-36). In a variation of this example, a fluorescent tracer molecule may compete with the substrate for the analyte to detect kinase activity by a technique which is known to those skilled in the art as indirect fluorescence polarization. Another technique for drug screening, which may be used, provides for high throughput screening of compounds having suitable binding affinity to the protein of interest as described in published PCT application WO84/03564. In this method, as applied to the proteins of the invention large numbers of different small test compounds are synthesised on a solid substrate, such as plastic pins or some other surface. The test compounds are reacted with a protein of the invention, or fragments thereof, and washed. Bound proteins are then detected by methods well known in the art. Purified proteins can also be coated directly onto plates for use in the aforementioned drug screening techniques. Alternatively, non-neutralizing antibodies can be used to capture the peptide and immobilise it on a solid support.

In another embodiment, one may use competitive drug screening assays in which neutralising antibodies capable of binding a protein of the invention specifically compete with a test compound for binding the protein of the invention. In this manner, the antibodies can be used to detect the presence of any peptide, which shares one or more antigenic determinants with Dgk epsilon, synaptojanin, G alpha 49B, CG 13609, Rab8, Delta, Nup214, Malvolio, or Fasciclin 1 or a homologous protein.

The nucleic acids encoding the proteins of the invention can be used to generate transgenic animals or site-specific gene modifications in cell lines. These transgenic non-human animals are useful in the study of the function and regulation of the proteins of the invention in vivo. Transgenic animals, particularly mammalian transgenic animals, can serve as a model system for the investigation of many developmental and cellular processes common to humans. A variety of non-human models of metabolic disorders can be used to test effectors/modulators of the proteins of the invention. Misexpression (for example, overexpression or lack of expression) of a protein of the invention, particular feeding conditions, and/or administration of biologically active compounds can create models of metablic disorders. ln one embodiment of the invention, such assays use mouse models of insulin resistance and/or diabetes, such as mice carrying gene knockouts in the leptin pathway (for example, ob (leptin) or db (leptin receptor) mice) . Such mice develop typical symptoms of diabetes, show hepatic lipid accumulation and frequently have increased plasma lipid levels (see Bruning et al, 1 998, Mol. Cell. 2:449-569) . Susceptible wild type mice (for example C57BI/6) show similiar symptoms if fed a high fat diet. In addition to testing the expression of the proteins of the invention in such mouse strains (see Examples section), these mice could be used to test whether administration of a candidate effector/modulator alters for example lipid accumulation in the liver, in plasma, or adipose tissues using standard assays well known in the art, such as FPLC, colorimetric assays, blood glucose level tests, insulin tolerance tests and others.

Transgenic animals may be made through homologous recombination in non-human embryonic stem cells, where the normal locus of the gene encoding a protein of the invention is altered. Alternatively, a nucleic acid construct encoding a protein of the invention is injected into oocytes and is randomly integrated into the genome. Vectors for stable integration include plasmids, retroviruses and other animal viruses, yeast artificial chromosomes (YACs), and the like. The modified cells or animal are useful in the study of the function and regulation of the proteins of the invention. For example, a series of small deletions and/or substitutions may be made in the gene that encodes a protein of the invention to determine the role of particular domains of the protein, functions in pancreatic differentiation, etc.

Furthermore, variants of the genes of the invention like specific constructs of interest include anti-sense molecules, which will block the expression of the proteins of the invention, or expression of dominant negative mutations. A detectable marker, such as for example lac-Z or luciferase may be introduced in the locus of a gene of the invention, where up regulation of expression of the genes of the invention will result in an easily detected change in phenotype.

One may also provide for expression of the genes of the invention or variants thereof in cells or tissues where it is not normally expressed or at abnormal times of development. In addition, by providing expression of the proteins of the invention in cells in which they are not normally produced, one can induce changes in cell behavior.

DNA constructs for homologous recombination will comprise at least portions of the genes of the invention with the desired genetic modification, and will include regions of homology to the target locus. DNA constructs for random integration do not need to contain regions of homology to mediate recombination. Conveniently, markers for positive and negative selection are included. DNA constructs for random integration will consist of the nucleic acids encoding the proteins of the invention, a regulatory element (promoter), an intron and a poly-adenylation signal. Methods for generating cells having targeted gene modifications through homologous recombination are known in the art. For non-human embryonic stem (ES) cells, an ES cell line may be employed, or embryonic cells may be obtained freshly from a host, e.g. mouse, rat, guinea pig, etc. Such cells are grown on an appropriate fibroblast-feeder layer and are grown in the presence of leukemia inhibiting factor (LIF).

When non-human ES or embryonic cells or somatic pluripotent stem cells have been transfected, they may be used to produce transgenic animals. After transfection, the cells are plated onto a feeder layer in an appropriate medium. Cells containing the construct may be selected by employing a selective medium. After sufficient time for colonies to grow, they are picked and analyzed for the occurrence of homologous recombination or integration of the construct. Those colonies that are positive may then be used for embryo transfection and morula aggregation. Briefly, morulae are obtained from 4 to 6 week old superovulated females, the Zona Pellucida is removed and the morulae are put into small depressions of a tissue culture dish. The ES cells are trypsinized, and the modified cells are placed into the depression closely to the morulae. On the following day the aggregates are transfered into the uterine horns of pseudopregnant females. Females are then allowed to go to term. Chimeric offsprings can be readily detected by a change in coat color and are subsequently screened for the transmission of the mutation into the next generation (F1 -generation) . Offspring of the F1 -generation are screened for the presence of the modified gene and males and females having the modification are mated to produce homozygous progeny. If the gene alterations cause lethality at some point in development, tissues or organs can be maintained as allogenic or congenic grafts or transplants, or in vitro culture. The transgenic animals may be any non-human mammal, such as laboratory animal, domestic animals, etc., for example, mouse, rat, guinea pig, sheep, cow, pig, and others. The transgenic animals may be used in functional studies, drug screening, and other applications and are useful in the study of the function and regulation of the proteins of the invention in vivo.

Finally, the invention also relates to a kit comprising at least one of

(a) a nucleic acid molecule coding for a protein of the invention or a functional fragment thereof;

(b) a protein of the invention or a functional fragment or an isoform thereof;

(c) a vector comprising the nucleic acid of (a);

(d) a host cell comprising the nucleic acid of (a) or the vector of (c);

(e) a polypeptide encoded by the nucleic acid of (a);

(f) a fusion polypeptide encoded by the nucleic acid of (a); (g) an antibody, an aptamer or another effector/modulator of the nucleic acid of (a) or the polypeptide of (b), (e), or (f) and (h) an anti-sense oligonucleotide of the nucleic acid of (a) . The kit may be used for diagnostic or therapeutic purposes or for screening applications as described above. The kit may further contain user instructions.

The Figures show:

Figure 1 shows the triglyceride content of a Drosophila Dgk epsilon mutant. Shown is the change of triglyceride content of HD-EP(2)21475 flies caused by integration of the P-vector into the cDNA of Dgk epsilon (referred to as 'HD-EP21475/CyO', column 2) in comparison to controls (referred to as 'EP-control', column 1 ).

Figure 2 shows the molecular organization of the mutated Dgk epsilon gene locus.

Figure 3 shows the BLASTP search result for the Dgk epsilon gene product (Query) with the best human homologous match (Sbjct).

Figure 4 shows the expression of the Dgk epsilon homolog in mammalian tissues.

Figure 4A shows the real-time PCR analysis of Dgke expression in wild-type mouse tissues.

Figure 4B shows the real-time PCR analysis of Dgke expression in different mouse models.

Figure 4C shows the real-time PCR analysis of Dgke expression in mice fed with a high fat diet compared to mice fed with a standard diet.

Figure 5 shows triglyceride content of a Drosophila synaptojanin mutant. Shown is the change of triglyceride content of HD-EP(2)20255 flies caused by integration of the P-vector into the cDNA of the synaptojanin gene (referred to as 'HD-EP20255', column 2) in comparison to controls (referred to as 'EP-control', column 1 ).

Figure 6 shows the molecular organization of the mutated synaptojanin gene locus.

Figure 7 shows the BLASTP search results for the synaptojanin gene product (Query) with the three best human homologous matches (Sbjct).

Figure 8 shows the expression of a synaptojanin homolog in mammalian tissues.

Figure 8A shows the real-time PCR analysis of Synaptojanin 1 expression in wild-type mouse tissues.

Figure 8B shows the real-time PCR analysis of Synaptojanin 1 expression in different mouse models.

Figure 8C shows the real-time PCR analysis of Synaptojanin 1 expression in mice fed with a high fat diet compared to mice fed with a standard diet.

Figure 8D shows the real-time PCR analysis of Synaptojanin 1 expression during the differentiation of 3T3-L1 cells from preadipocytes to mature adipocytes.

Figure 9 shows the expression of the synaptojanin homologs in mammalian (human) tissue.

Figure 9A shows the quantitative analysis of synaptojanin 1 (SYNJ1 ) expression in human abdominal adipocyte cells, during the differentiation from preadipocytes to mature adipocytes.

Figure 9B shows the quantitative analysis of synaptojanin 2 (SYNJ2) expression in human abdominal adipocyte cells, during the differentiation from preadipocytes to mature adipocytes.

Figure 10 shows the triglyceride content of a Drosophila G alpha 49B mutant. Shown is the change of triglyceride content of HD-EP(2)20545 flies caused by integration of the P-vector into the cDNA of the G alpha 49B gene (referred to as 'HD-EP20545/CyO', column 2) in comparison to controls (referred to as 'EP-control', column 1 ), the change of triglyceride content of HD-EP(2)20545 flies caused by ectopic expression of the gene in the fat body (referred to as 'HD-EP20545/FB', column 4) in comparison to controls (referred to as 'random EP/FB', column 3), and the change of triglyceride content of HD-EP(2) 20545 flies caused by ectopic expression of the gene in the neurons ('HD-EP20545/elav', column 6) in comparison to controls (referred to as 'random EP/elav', column 5).

Figure 1 1 shows the molecular organization of the mutated G protein alpha 49B gene locus.

Figure 1 2 shows the BLASTP search result for the G protein alpha 49B gene product (Query) with the three best human homologous matches (Sbjct).

Figure 13 shows the expression of a G protein alpha 49B homolog in mammalian tissues. Figure 13A shows the real-time PCR analysis of Gna1 1 expression in wild-type mouse tissues.

Figure 13B shows the real-time PCR analysis of Gna1 1 expression in different mouse models.

Figure 13C shows the real-time PCR analysis of Gna1 1 expression in mice fed with a high fat diet compared to mice fed with a standard diet.

Figure 14 shows the triglyceride content of a Drosophila CG13609 mutant. Shown is the change of triglyceride content of HD-EP(3)35765 flies caused by integration of the P-vector into the cDNA of CG 13609 (referred to as 'HD-EP35765', column 2) in comparison to controls (referred to as 'EP-control', column 1 ). Figure 15 shows the molecular organization of the mutated CG 13609 (Gadfly Accession Number) gene locus.

Figure 16 shows the BLASTP search result for the CG13609 gene product (Query) with the best human homologous match (Sbjct).

Figure 17 shows the expression of a CG 13609 homolog in mammalian tissues.

Figure 17A shows the real-time PCR analysis of Ptovl expression in wild-type mouse tissues.

Figure 17B shows the real-time PCR analysis of Ptovl expression in different mouse models.

Figure 18 shows the triglyceride content of a Drosophila Rab8 mutant. Shown is the change of triglyceride content of HD-EP(3)37172 flies (referred to as 'HD-EP37172', column 2) and HD-EP(3)37173 flies (referred to as 'HD-EP37173', column 3) caused by integration of the P-vector into the cDNA of the Rab8 gene, in comparison to controls (referred to as 'EP-control', column 1 ).

Figure 19 shows the molecular organization of the mutated Rab8 (Gadfly Accession Number CG8287) gene locus.

Figure 20 shows the BLASTP search results for the Rab8 gene product (Query) with the two best human homologous matches (Sbjct).

Figure 21 shows the triglyceride content of a Drosophila Delta mutant. Shown is the change of triglyceride content of HD-EP(3)31745 flies caused by integration of the P-vector into the an intron of Delta (referred to as 'HD-EP31745', column 2) in comparison to controls (referred to as 'EP-control', column 1 ). Figure 22 shows the molecular organization of the mutated Delta gene locus.

Figure 23 shows the BLASTP search result for the Delta gene product (Query) with the best human homologous match (Sbjct).

Figure 24 shows the expression of a Delta homolog in mammalian tissues. Figure 24A shows the real-time PCR analysis of Dill expression in wild-type mouse tissues. Figure 24B shows the real-time PCR analysis of DII1 expression in different mouse models.

Figure 24C shows the real-time PCR analysis of DII1 expression in mice fed with a high fat diet compared to mice fed with a standard diet.

Figure 25 shows the triglyceride content of a Drosophila Nup214 mutant. Shown is the change of triglyceride content of triglyceride content of HD-EP(2) 20772 flies caused by integration of the P-vector into the promoter/enhancer region (referred to as 'HD-EP20772/CyO', column 2), by ectopic expression of the Nup214 gene mainly in the fat body of these flies (referred to as 'HD-EP20772/FB', column 3) and by ectopic expression of the Nup214 gene mainly in the neurons of these flies (referred to as 'HD-EP20772/elav', column 4) in comparison to controls (referred to as 'EP-control', column 1 ).

Figure 26 shows the molecular organization of the mutated Nup214 gene locus.

Figure 27 shows the BLASTP search results for the Nup214 gene product (Query) with the three best human homologous matches (Sbjct).

Figure 28 shows the triglyceride content of a Malvolio (Mvl) mutant. Shown is the change of triglyceride content of HD-EP(3)31625 flies caused by integration of the P-vector into the promoter/enhancer region (referred to as 'HD-EP31625/TM3,Ser', column 2), by ectopic expression of the Mvl gene mainly in the fat body of these flies (referred to as 'HD-EP31625/FB', column 3) and by ectopic expression of the Mvl gene mainly in the neurons of these flies (referred to as 'HD-EP31625/elav', column 4) in comparison to controls (referred to as 'EP-control', column 1 ).

Figure 29 shows the molecular organization of the mutated Mvl gene locus.

Figure 30 shows the BLASTP search results for the Mvl gene product (Query) with the six best human homologous matches (Sbjct).

Figure 31 shows the expression of the Mvl homologs in mammalian tissues. Figure 31 A shows the real-time PCR analysis of Slc1 1 a1 expression in wild-type mouse tissues.

Figure 31 B shows the real-time PCR analysis of Slc1 1 a1 expression in different mouse models.

Figure 31 C shows the real-time PCR analysis of Slc1 1 a1 expression in mice fed with a high fat diet compared to mice fed with a standard diet.

Figure 31 D shows the real-time PCR analysis of SIc1 1 a2 expression in wild-type mouse tissues.

Figure 31 E shows the real-time PCR analysis of Slc1 1 a2 expression in different mouse models. Figure 31 F shows the real-time PCR analysis of Sid 1 a2 expression during the differentiation of 3T3-L1 cells from preadipocytes to mature adipocytes.

Figure 32 shows the triglyceride content of a Drosophila Fasciclin 1 (Fas1 ) mutant. Shown is the change of of triglyceride content of HD-EP(3)35681

CHD-EP35681 ', column 2) flies and of HD-EP(3)32580 flies caused by integration of the P-vector into the an intron of Fas1 (referred to as 'HD-EP32580', column 3) in comparison to controls (referred to as 'EP-control', column 1 ).

Figure 33 shows the molecular organization of the mutated Fasl gene locus.

Figure 34 shows the BLASTP search result for the Fasl gene product (Query) with the three best human homologous matches (Sbjct).

Figure 35 shows the expression of a Fas l homolog in mammalian tissues.

Figure 35A shows the real-time PCR analysis of osteoblast specific factor-2

(OSF2)-pending expression in wild-type mouse tissues.

Figure 35B shows the real-time PCR analysis of OSF-2-pending expression in different mouse models. Figure 35C shows the real-time PCR analysis of OSF-2-pending expression in mice fed with a high fat diet compared to mice fed with a standard diet.

Figure 35D shows the real-time PCR analysis of OSF-2-pending expression during the differentiation of 3T3-L1 cells from preadipocytes to mature adipocytes.

Figure 36 shows the expression of a Fasl homolog in mammalian (human) tissue. Shown is the quantitative analysis of OSF-2 expression in human abdominal adipocyte cells, during the differentiation from preadipocytes to mature adipocytes.

The examples illustrate the invention:

Example 1 : Measurement of triglyceride content in Drosophila

Mutant flies are obtained from proprietary or publicly available fly mutation stock collections. The flies are grown under standard conditions known to those skilled in the art. In the course of the experiment, additional feedings with bakers yeast (Saccharomyces cerevisiae) are provided. The average change of triglyceride content of Drosophila containing the EP-vectors in homozygous viable or heterozygous viable/homozygous lethal integration was investigated in comparison to control flies (see Figures 1 , 5, 10, 14, 18, 21 , 25, 28, and 32). For determination of triglyceride, flies were incubated for 5 min at 90°C in an aqueous buffer using a waterbath, followed by hot extraction. After another 5 min incubation at 90°C and mild centrifugation, the triglyceride content of the flies extract was determined using Sigma Triglyceride (INT 336-10 or -20) assay by measuring changes in the optical density according to the manufacturer's protocol. As a reference the protein content of the same extract was measured using BIO-RAD DC Protein Assay according to the manufacturer's protocol. The assays were repeated several times.

The average triglyceride level of all flies of the EP collections (referred to as 'EP-control') is shown as 100% in the first columns in Figures 1 , 5, 10, 14, 18, 21 , 25, 28, and 32, respectively. The average triglyceride level of all flies containing the FB- Gal4 vector (referred to as 'random EP/FB') is shown as 100% in the third column in Figure 10. The average triglyceride level of all flies containing the elav- Gal4 vector (referred to as 'random EP/elav') is shown as 100% in the fifth column in Figure 10. Standard deviations of the measurements are shown as thin bars.

HD-EP(2)21475 heterozygous flies (column 2 in Figure 1 , 'HD-EP21475/CyO'), HD-EP(2)20255 homozygous flies (column 2 in Figure 5), HD-EP(3)37172 homozygous flies (column 2 in Figure 18), HD-EP(3)37173 homozygous flies (column 3 in Figure 18), HD-EP(3)31745 homozygous flies (column 2 in Figure 21 ), HD-EP(3)35618 homozygous flies (column 2 in Figure 32), and HD-EP(3)32580 homozygous flies (column 3 in Figure 32) show constantly a higher triglyceride content than the controls. HD-EP(2)20545 heterozygous flies (column 2 in Figure 10, 'HD-EP20545/CyO') and HD-EP(3)35765 homozygous flies (column 2 in Figure 14) show constantly a lower triglyceride content than the controls. Therefore, the loss of gene activity in the loci where the EP-vectors are viably integrated, is responsible for changes in the metabolism of the energy storage triglycerides. The findings suggest the presence of similar functions of the homologous proteins in humans.

HD-EP(2)20545 males are crossed to FB-Gal4 or elav-Gal4 virgins. The offspring is carrying a copy of the HD-EP(3)35765 vector and a copy of the FB-Gal4 ('HD-EP20545/FB') or the elav-Gal4 ('HD-EP20545/elav') vector, leading to ectopic expression of adjacent genomic DNA sequences 3' of the HD-EP(2)20545 integration locus, mainly in the fatbody or neurons of these flies. 'HD-EP20545/FB' flies show constantly a lower triglyceride content (column 4 in Figure 10) than the control EP-collection that is crossed to FB-Gal4 (referred to as 'random EP/FB', column 3 in Figure 10). 'HD-EP20545/elav' flies show constantly a slightly lower triglyceride content (column 6 in Figure 10) in comparison to the control EP-collection that is crossed to elav-Gal4 (referred to as 'random EP/elav', column 5 in Figure 10). Therefore, the gain of gene activity in the locus, where the EP-vector of HD-EP(2) 20545 flies is integrated 5' of the G protein alpha 49B gene, is responsible for changes in the metabolism of the energy storage triglycerides.

HD-EP(2)20772 heterozygous flies (column 2 in Figure 25, 'HD-EP20772/CyO') show constantly a slightly higher triglyceride content than the controls. HD-EP(2)20772 males are crossed to FB-Gal4 or elav-Gal4 virgins. The offspring is carrying a copy of the HD-EP(2)20772 vector and a copy of the FB-Gal4 ('HD-EP20772/FB') or elav-Gal4 ('HD-EP20772/elav') vector, leading to ectopic expression of adjacent genomic DNA sequences 3' of the HD-EP(2)20772 integration locus, mainly in the fatbody or neurons of these flies. 'HD-EP20772/FB' flies show constantly a higher triglyceride content (column 3 in Figure 25) than the control EP-collection that is crossed to FB-Gal4. 'HD-EP20772/elav' flies show constantly a lower triglyceride content (column 4 in Figure 25) than the control EP-collection that is crossed to elav-Gal4. Therefore, the gain of gene activity in the locus, where the EP-vector of HD-EP(2)20772 flies is integrated 5' of the Nup214 gene, is responsible for changes in the metabolism of the energy storage triglycerides.

HD-EP(3)31625 heterozygous flies (column 2 in Figure 28, 'HD-EP31625/TM3, Ser') show the same triglyceride content as the controls. HD-EP(3)31625 males are crossed to FB-Gal4 or elav-Gal4 virgins. The offspring is carrying a copy of the HD-EP(3)31625 vector and a copy of the FB-Gal4 ('HD-EP31625/FB') or elav-Gal4 ('HD-EP31625/elav') vector, leading to ectopic expression of adjacent genomic DNA sequences 3' of the HD-EP(3)31625 integration locus, mainly in the fatbody or neurons of these flies. 'HD-EP31625/FB' flies show constantly a slightly higher triglyceride content (column 3 in Figure 28) than the control EP-collection that is crossed to FB-Gal4. 'HD-EP31625/elav' flies show constantly a higher triglyceride content (column 4 in Figure 28) than the control EP-collection that is crossed to elav-Gal4. Therefore, the gain of gene activity in the locus, where the EP-vector of HD-EP(3)31625 flies is integrated 5' of the Malvolio gene, is responsible for changes in the metabolism of the energy storage triglycerides. The findings suggest the presence of similar functions of the homologous proteins in humans.

Example 2: Identification of Drosophila genes associated with triglyceride metabolism

Nucleic acids encoding the proteins of the present invention were identified using a plasmid-rescue technique. Genomic DNA sequences were isolated that are localized adjacent to the EP vector (herein HD-EP(2)21 75, HD-EP(2)20255, HD-EP(2)20545, HD-EP(3)35765, HD-EP(3)37172, HD-EP(3)37173, HD-EP(3)31745, HD-EP(2)20772, HD-EP(3)31625, HD-EP(3)35618, or HD-EP(3)32580) integration. Using those isolated genomic sequences public databases like Berkeley Drosophila Genome Project (GadFly) were screened, thereby identifying the integration sites of the vectors, and the corresponding genes. The molecular organization of these gene loci is shown in Figures 2, 6, 1 1 , 15, 19, 22, 26, 29, and 33.

In Figures 2, 15, 19, 26, 29, and 33 and in the upper half of Figures 6 and 22, genomic DNA sequence is represented by the assembly as a dotted grey line in the middle that includes the integration sites of the vectors for lines HD-EP(2)21475, HD-EP(2)20255, HD-EP(3)35765, HD-EP(3)37172, HD-EP(3)37173, HD-EP(3)31745, HD-EP(2)20772, HD-EP(3)31625, HD-EP(3)35618, or HD-EP(3)32580. Numbers represent the coordinates of the genomic DNA. The upper parts of the figures represent the sense strand " + ", the lower parts represent the antisense strand "-". The insertion sites of the P-elements in the Drosophila lines are shown as triangles or boxes in the "P-elements + " or "P-elements -" lines. Transcribed DNA sequences (ESTs) are shown as grey bars in the "EST + ", "EST -", "IPI + ", and/or the "IPI -" lines, and predicted cDNAs are shown as bars in the "cDNA + " and/ or "cDNA -" lines. Predicted exons of the cDNAs are shown as dark grey bars and introns are shown as light grey bars.

The HD-EP(2)21475) vector is homozygous lethal/heterozygous viable integrated into the cDNA (base pair 1896 or 2078) of a Drosophila gene in sense orientation, identified as Diacyl glycerol kinase epsilon (Dgk epsilon; GadFly Accession Number CG8657; GenBank Accession Number AY050241 for the cDNA, AAK84940, AAF58458, and AAB97514 for the protein). The chromosomal localization site of the integration of the vector of HD-EP(2)21475 is at gene locus 2R, 49D4. In Figure 2, the coordinates of the genomic DNA are starting at position 7758200 on chromosome 2R, ending at position 7762000. The insertion site of the P-element in Drosophila HD-EP(2)21475 is shown as bar in the "P Elements + " line and is labeled. The predicted cDNA of the Dgk epsilon gene shown in the "cDNA + " line is labeled, the corresponding ESTs are shown in the "EST + " line. The predicted cDNA of the Nac alpha gene shown in the "cDNA -" line is also labeled, the corresponding ESTs are shown in the "EST + " line.

The HD-EP(2)20255 vector is homozygous viable integrated into the first intron of the CG6562-RB transcript and into the promoter/enhancer region of the CG6562-RA transcript of a Drosophila gene in antisense orientation, identified as synaptojanin (GadFly Accession Number CG6562). The chromosomal localization site of the integration of the vector of

HD-EP(2)20255 is at gene locus 58D1 on chromosome 2R. In the upper part of Figure 6, the coordinates of the genomic DNA are starting at position 17003637 on chromosome 2R, ending at position 17009987. The insertion site of the P-element in Drosophila HD-EP(2)20255 line is shown as triangle in the "P Elements -" line and is labeled. The predicted cDNA of the synaptojanin gene shown in the "cDNA + " line is labeled ('CG6562'), the corresponding ESTs are shown in the "EST + " line. In the lower part of Figure 6 the molecular organization of the synapojanin gene is shown, as annotated by FlyBase GadFly Genome Annotation Database.

The HD-EP(3)35765) vector is homozygous viable integrated into the cDNA (base pairs 58/59) of a Drosophila gene in antisense orientation, identified as CG 13609 (GadFly Accession Number). The chromosomal localization site of the integration of the vector of HD-EP(3)35765 is at gene locus 3R, 95F3. In Figure 15, the coordinates of the genomic DNA are starting at position 19960261 on chromosome 3R, ending at position 19961824. The insertion site of the P-element in Drosophila HD-EP(3)35765 line is shown as arrow in the "P Elements -" line and is labeled. The predicted cDNA of the CG13609 gene shown in the "cDNA + " line is labeled, the corresponding EST is shown in the "IPI + " line.

The HD-EP(3)37172 and HD-EP(3)37173 vectors are homozygous viable integrated into the cDNA (base pairs 250 and 257 of the EST RE12815, respectively) of a Drosophila gene in antisense orientation and sense oritentation, respectively, identified as Rab-protein 8 (Rab8; GadFly Accession Number CG8287, GenBank Accession Numbers D84374 and NM_079448.1 for the cDNA, BAA2171 1 and NP_524172.1 for the protein) . The chromosomal localization site of the integration of the vectors of HD-EP(3)37172 and HD-EP(3)37173 is at gene locus 76D2 on chromosome 3L. In Figure 19 the coordinates of the genomic DNA are starting at position 19718968 on chromosome 3L, ending at position

19723968. The insertion site of the P-element in Drosophila HD-EP(3)37172 line is shown as arrow in the "P Elements + " line and is labeled, the insertion site of the P-element in Drosophila HD-EP(3)37173 line is shown as arrow in the "P Elements -" line and is labeled. The predicted cDNA of the Rabδ gene shown in the "cDNA -" line is labeled, the corresponding ESTs are shown in the "EST -" and the "IPI -" lines.

The HD-EP(3)31745 vector is homozygous viable integrated into an intron of a Drosophila gene in sense orientation, identified as Delta (DI, GadFly Accession Number CG3619, GenBank Accession Number NM 05916 for the cDNA, NP_477264 for the protein). The chromosomal localization site of the integration of the vector of HD- HD-EP(3)31745 is at gene locus 3R, 92A1-2. In the upper part of Figure 22, the coordinates of the genomic DNA are starting at position 15055000 on chromosome 3R, ending at position 15095000. The insertion site of the P-element in Drosophila HD-EP(3)31745 line is shown as arrow in the "P Elements -" line and is labeled. The predicted cDNA of the Delta gene shown in the "cDNA -" line is labeled, the corresponding ESTs are shown in the "EST -" and the "IPI -" lines. In the lower part of Figure 22 the molecular organization of the Delta gene is shown, as annotated by Flybase.

The HD-EP(2)20772 vector is homozygous lethal/heterozygous viable integrated 5' of a Drosophila gene in sense orientation, identified as Nup214 (GadFly Accession Number CG3820, GenBank Accession Numbers NM_143782 for the cDNA, NP_652039, AAF46928, and AAM1 1320 for the protein). The chromosomal localization site of the integration of the vectors of HD-EP(2)20772 is at gene locus 59C2 on chromosome 2R. In Figure 26, the coordinates of the genomic DNA are starting at position 17840640 on chromosome 2R, ending at position 17853140. The insertion site of the P-element in Drosophila HD-EP(2)20772 line is shown as arrow in the "P Elements -" line and is labeled. The predicted cDNA of the Nup214 gene shown in the "cDNA -" line is labeled, the corresponding ESTs are shown in the "EST -" and the "IPI -" lines.

The HD-EP(3)31625 vector is homozygous lethal/heterozygous viable integrated about 240 base pairs 5' of a Drosophila gene in sense orientation, identified as Malvolio (Mvl; GadFly Accession Number CG3671 ; GenBank Accession Number NM 079701 for the cDNA, NP 524425.1 for the protein). The chromosomal localization site of integration of the vector of HD-EP(3)31625 is at gene locus 3R, 93B5. In Figure 29, the coordinates of the genomic DNA are starting at position 16805995 on chromosome 3R, ending at position 16812245. The insertion site of the P-element in Drosophila HD-EP(3)31625 line is shown as arrow in the "P Elements -" line and is labeled. The predicted cDNA of the Mvl gene shown in the "cDNA -" line is labeled, the corresponding ESTs are shown in the "EST -" and "IPI -" lines.

The HD-EP(3)35618 and HD-EP(3)32580 vectors are homozygous viable integrated into the cDNA (base pairs 46 and 33 of the EST clones RE33069 and RE23507, respectively) of a Drosophila gene in sense and antisense orientation, respectively, identified as Fasciclin 1 (Fasl ; GadFly Accession Number CG6588, GenBank Accession Numbers AY118531 for the cDNA, AAM49900.1 for the protein). The chromosomal localization site of the integration of the vectors of HD-EP(3)35618 and HD-EP(3)32580 is at gene locus 89D5-6 on chromosome 3R. In Figure 33, the coordinates of the genomic DNA are starting at position 12378753 on chromosome 3R, ending at position 12403753. The insertion site of the P-element in Drosophila HD-EP(3)35618 line is shown as arrow in the "P Elements + " line and is labeled, the insertion site of the P-element in Drosophila HD-EP(3)32580 line is shown as arrow in the "P Elements -" line and is labeled. The predicted cDNA of the Fasl gene shown in the "cDNA + " line is labeled, the corresponding ESTs are shown in the "EST + " line.

The HD-EP(2)20545 vector is homozygous lethal/heterozygous viable integrated into the cDNA (base pairs 39/40) of a Drosophila gene in sense orientation, identified as G protein alpha 49B (G alpha 49B; GadFly Accession Number CG17759, GenBank Accession Numbers NM_078994, NP_523718, AAF58485, AAA28460, AAC46943). Figure 1 1 shows the molecular organization of this gene locus. The chromosomal localization site of the integration of the vector of HD-EP(2)20545 is at gene locus 49C1 on chromosome 2R. In Figure 1 1 , genomic DNA sequence is represented by the assembly as a black scaled double-headed arrow that includes the integration sites of vector for line HD-EP(2)20545. Ticks represent the length of the genomic DNA (1000 base pairs per tick). The grey arrows in the upper part of the figure represent BAG clones, the black arrow in the topmost part of the figure represents the section of the chromosome. The insertion site of the P-element in Drosophila HD-EP(2)20545 is shown as arrow and is labeled. The cDNA sequences of the predicted genes (as predicted by the Berkeley Drosophila Genome Project, GadFly and by Magpie) are shown as dark grey bars (exons), linked by dark grey lines (introns), and are labeled (see also key at the bottom of the figure). Two variants of the G alpha 49B gene are shown in the middle and are labeled.

Expression of the genes described above could be effected by integration of the vectors into the transcription units, leading to a change in the amount of the energy storage triglycerides.

Example 3: Identification of human homologous genes and proteins

The Drosophila genes and proteins encoded thereby with functions in the regulation of triglyceride metabolism were further analysed using the BLAST algorithm searching in publicly available sequence databases and mammalian homologs were identified (see Table 1 and Figures 3, 7, 12, 16, 20, 23, 27, 30, and 34).

The term "polynucleotide comprising the nucleotide sequence as shown in GenBank Accession number" relates to the expressible gene of the nucleotide sequences deposited under the corresponding GenBank Accession number. The term "GenBank Accession number" relates to NCBI GenBank database entries (Ref.: Benson et al., Nucleic Acids Res. 28 (2000) 15-18). Sequences homologous to Drosphila Dgk epsilon, synaptojanin, G alpha 49B, CG 13609, Rab8, Delta, Nup214, Malvolio, or Fasciclin 1 were identified using the publicly available program BLASTP 2.2.3 of the non-redundant protein data base of the National Center for Biotechnology Information (NCBI) (see, Altschul et al., 1997, Nucleic Acids Res. 25:3389-3402). Table 1 : Human homologs of the Drosophila (Dm) genes

Dgk epsilon, synaptojanin, G alpha 49B, CG 13609, Rab8, Delta, Nup214, Malvolio, or Fasciclin 1 homologous proteins and nucleic acid molecules coding therefore are obtainable from insect or vertebrate species, e.g. mammals or birds. Particularly preferred are nucleic acids as described in Table 1 .

As shown in Figure 3, gene product of Dgk epsilon (Diacyl glycerol kinase epsilon; GadFly Accession Number CG8657; GenBank Accession Number AY050241 for the cDNA, AAK84940, AAF58458, and AAB97514 for the protein) is 54% homologous to human diacylglycerol kinase epsilon (GenBank Accession Number NP_003638.1 for the protein, NM 003647 for the cDNA). Dgk epsilon also shows 55% homology on protein level to mouse diacylglycerol kinase epsilon (GenBank Accession Number NP_062378.1 ).

As shown in Figure 7, gene product of Drosophila synaptojanin (GadFly Accession Number CG6562) is 63% homologous to human KIAA0910 protein (GenBank Accession Number BAA74933.2 for the protein, AB020717 for the cDNA), 61 % homologous to human synaptojanin (GenBank Accession Number AAC51921 .1 for the protein, AF009039 for the cDNA), and 61 % homologous to human synaptojanin 1 ; inositol 5'-phosphatase (GenBank Accession Number NP_003886.1 for the protein, NM_003895 for the cDNA). Drosophila synaptojanin also shows 68% homology on protein level to mouse predicted protein IPI001 16009.1 (ENSEMBL Accession Number ENSMUSP00000035543).

As shown in Figure 12, gene product of Drosophila G alpha 49B (GadFly Accession Number CG17759, GenBank Accession Numbers NM_078994, NP_523718, AAF58485, AAA28460, AAC46943) is 90% homologous to human G alpha q protein (GenBank Accession Number AAG61 1 17.1 for the protein, AF329284 for the cDNA), 90% homologous to human Guanine nucleotide-binding protein G(q), alpha subunit (GenBank Accession Number P50148), and 90% homologous to human Guanine nucleotide-binding protein G(Y), alpha subunit (Alpha-1 1 ) (GenBank Accession Number P29992). G alpha 49B also shows 90% homology on protein level to mouse protein similar to guanine nucleotide binding protein, alpha q polypeptide (GenBank Accession Number XP 123396.1 ) and 91 % homologous to mouse guanine nucleotide-binding protein G(q), alpha subunit.

As shown in Figure 16, gene product of CG 13609 (GadFly Accession Number) is 49% homologous to human prostate tumor over expressed gene 1 (PTOV1 , GenBank Accession Number NP_059128.1 for the protein, NM_017432 for the cDNA). CG13609 also shows 47% homology on protein level to mouse prostate tumor over expressed gene 1 (GenBank Accession Number NP 598710.1 ).

As shown in Figure 20, gene product of Drosophila Rab8 (GadFly Accession Number CG8287, GenBank Accession Numbers D84374 and NM 079448.1 for the cDNA, BAA2171 1 and NP_524172.1 for the protein) is 88% homologous to human mel transforming oncogene; ras-associated protein RAB8 (GenBank Accession Number NP_005361.2 for the protein, NM_005370 for the cDNA), and 87% homologous to human RAB8-b protein (GenBank Accession Number NP 057614.1 for the protein, NM 01 6530 for the cDNA). Drosophila Rab8 also shows 80% homology on protein level to human RAB13, member RAS oncogene family (GenBank Accession Number NP 002861 .1 for the protein, NM_002870 for the cDNA).

As shown in Figure 23, gene product of Drosophila Delta (GadFly Accession Number CG3619, GenBank Accession Number NM_05916 for the cDNA, NP_477264 for the protein) is 58% homologous to human delta-like 1 (mouse) homolog (protein similar to dJ894D12.3; GenBank Accession Number XP 035684.1 for the protein, XM_035684 for the cDNA). Delta also shows 58% homology on protein level to mouse delta-like 1 (Drosophila); delta-like 1 homolog (Drosophila) (GenBank Accession Number NP_031893.1 ).

As shown in Figure 27, gene product of Drosophila Nup214 (GadFly Accession Number CG3820, GenBank Accession Numbers NM 143782 for the cDNA, NP 652039, AAF46928, and AAM 1 1320 for the protein) is 39% homologous to human protein similar to nucleoporin 214kD (GenBank Accession Number XP 033360.6 for the protein, XM 033360 for the cDNA), 39% homologous to human nucleoporin 214kD (CAIN; GenBank Accession Number NP_005076.1 for the protein, NM_005085 for the cDNA), and 39% homologous to human KIAA0023 protein (GenBank Accession Number BAA03515.1 for the protein, D14689 for the cDNA). Nup21 also shows 38% homology on protein level to mouse protein IPI00136918.1 (ENSEMBL Accession Number ENSMUSP0000000191 1 ).

As shown in Figure 30, gene product of Drosophila Fasl (GadFly Accession Number CG6588, GenBank Accession Numbers AY1 18531 for the cDNA, AAM49900.1 for the protein) is 35% homologous to human osteoblast specific factor 2 (fasciclin l-like; GenBank Accession Number XP_017432.2 for the protein, XM_017432 for the cDNA) and 43% homologous to human osteoblast specific factor 2 (GenBank Accession Number S361 1 1 ). Fasl also shows 36% homology on protein level to mouse protein similar to osteoblast specific factor 2 (fasciclin l-like; GenBank Accession Numbers AAH31449.1 (783 amino acids) and NP_56559.1 (81 1 amino acids)).

As shown in Figure 34, gene product of Mvl (Malvolio; GadFly Accession Number CG3671 ; GenBank Accession Number NM_079701 for the cDNA, NP_524425.1 for the protein) is 80% homologous to human integral membrane protein (GenBank Accession Number I57022), 78% homologous to human solute carrier family 1 1 (proton-coupled divalent metal ion transporters), member 2 (GenBank Accession Number XP 051 166.2 for the protein, XM_051 166 for the cDNA), 78% homologous to human solute carrier family 1 1 (proton-coupled divalent metal ion transporters), member 2 (natural resistance-associated macrophage protein 2; GenBank Accession Number NP 000608.1 for the protein, NM_000617 for the cDNA), 78% homologous to human natural resistence-associated macrophage protein 2 (GenBank Accession Number BAA34374.1 for the protein, AB015355 for the cDNA), 73% homologous to human solute carrier family 1 1 (sodium/phosphate symporters), member 1 (GenBank Accession Number XP 002585.4 for the protein, XM_002585 for the cDNA), and 76% homologous to human Nramp (GenBank Accession Number BAA07370.1 for the protein, D38171 for the cDNA).

DGKE is also referred to as human diacylglycerol kinase (DGK) epsilon protein in patent US6221658-B1 and as human diacylglycerol kinase epsilon protein sequence in patent US5976875-A. SYNJ1 is also referred to as Genbank Accession Numbers AB020717 and AF009039. GNA1 1 is also referred to as Genbank Accession Number P29992 for the protein, and as human G-protein alpha subunit 1 1 in patent application WO0136446. GNAQ is also referred to as Genbank Accession Number AF329284 for the cDNA, AAG61 1 17.1 and P50148 for the protein. Rabδb is also referred to as human protein sequence SEQ ID NO: 10930 in patent application EP1074617, as human 27423 G-protein in patent application WO0164887, and as hypoxia-regulated protein #78 in patent application WO0246465. DIM is also referred to as Genbank Accession Number XM 035.684 for the cDNA, XP 035684 for the protein, and as human notch ligand delta-like 1 protein in patent application WO02077204. Nup214 is also referred to as Genbank Accession Number XM_033360 for the cDNA, XP_033360 for the protein. SLC1 1 A1 is also referred to as Genbank Accession Number XM_002585 for the cDNA, XP_002585 for the protein, and SLC1 1A2 is also referred to as Genbank Accession Number XM 051 166 for the cDNA, XP 051 166 for the protein. OSF-2 is also referred to as Genbank Accession Number XM 017432 for the cDNA, XP_017432 and S361 1 1 for the protein, and as human allergy-associated protein SEQ ID No 33 in patent application WO02052006.

Example 4: Genetic adipose pathway screen

Adipose (adp) is a protein that has been described as regulating, causing or contributing to obesity in an animal or human (see WO 01 /96371 ). Transgenic flies containing a wild type copy of the adipose cDNA under the control of the Gal4/UAS system were generated (Brand and Perrimon, 1993, Development 1 18:401 -415; for adipose cDNA, see WO 01 /96371 ) . Chromosomal recombination of these transgenic flies with an eyeless-Gal4 driver line has been used to generate a stable recombinant fly line (herein referred to as eye-adp-Gal4) over-expressing adipose in the developing Drosophila eye. Animals receiving transgenic adipose activity under these conditions developed into adult flies with a visible change of eye phenotype. Virgins of the recombinant driver line were crossed with males of the mutant EP-line collection in single crosses and kept for preferably 12 to 15 days at 29°C. The offspring was checked for modifications of the eye phenotype (enhancement or suppression). Mutations changing the eye phenotype affect genes that modify adipose activity. The inventors have found that the fly line HD-EP(2)20255 is a suppressor of the eye-adp-Gal4 induced eye phenotype. This result is strongly suggesting an interaction of the synaptojanin gene with adipose since the integration of HD-EP(2)20255 was found to be located at the synaptojanin locus. This is supporting the function of synaptojanin and homologous proteins in the regulation of the energy homeostasis. Example 5: Expression of the polypeptides in mammalian (mouse) tissues

For analyzing the expression of the polypeptides disclosed in this invention in mammalian tissues, several mouse strains (preferrably mice strains C57BI/6J, C57BI/6 ob/ob and C57BI/KS db/db which are standard model systems in obesity and diabetes research) were purchased from Harlan Winkelmann (33178 Borchen, Germany) and maintained under constant temperature (preferrably 22°C), 40 per cent humidity and a light / dark cycle of preferrably 14 / 10 hours. The mice were fed a standard chow (for example, from ssniff Spezialitaten GmbH, order number ssniff M-Z V1 126-000). For the fasting experiment ("fasted wild type mice"), wild type mice were starved for 48 h without food, but only water supplied ad libitum (see, for example, Schnetzler et al., (1993) J Clin Invest 92(1 ):272-280, Mizuno et al., (1996) Proc Natl Acad Sci U S A 93(8):3434-3438). In a further experiment wild-type (wt) mice were fed a control diet (preferably Altromin C1057 mod control, 4.5% crude fat) or high fat diet (preferably Altromin C1057mod. high fat, 23.5% crude fat). Animals were sacrificed at an age of 6 to 8 weeks. The animal tissues were isolated according to standard procedures known to those skilled in the art, snap frozen in liquid nitrogen and stored at -80°C until needed.

RNA was isolated from tissues and cells using Trizol Reagent (for example, from Invitrogen, Karlsruhe, Germany) and further purified with the RNeasy Kit (for example, from Qiagen, Germany) in combination with an DNase-treatment according to the instructions of the manufacturers and as known to those skilled in the art. Total RNA was reverse transcribed (preferrably using Superscript II RNaseH- Reverse Transcriptase, from Invitrogen, Karlsruhe, Germany) and subjected to Taqman analysis preferrably using the Taqman 2xPCR Master Mix (from Applied Biosystems, Weiterstadt, Germany; the Mix contains according to the Manufacturer for example AmpliTaq Gold DNA Polymerase, AmpErase UNG, dNTPs with dUTP, passive reference Rox and optimized buffer components) on a GeneAmp 5700 Sequence Detection System (from Applied Biosystems, Weiterstadt, Germany).

Taqman analysis was performed preferrably using the following primer/probe pairs:

For the amplification of mouse diacylglycerol kinase, epsilon (Dgke) (SEQ ID NO: 1 ): 5'- GAG ATC ATG CTC AAG AAC GAC AA -3'; mouse Dgke reverse primer (SEQ ID NO: 2): 5'- TGC CGC GGA TCC AGT G -3'; Taqman probe (SEQ ID NO: 3): (5/6-FAM) CCG CAG ATG CCA TGC CCC A (5/6-TAMRA).

For the amplification of mouse Synaptojanin 1 (SEQ ID NO: 4): 5'- CAG TTC CGC AGC ATA GCG TT -3'; mouse Synaptojanin 1 reverse primer (SEQ ID NO: 5): 5'- CGG CTA ACT TGG GAG CGT C -3'; Taqman probe (SEQ ID NO: 6): (5/6-FAM) AAG AAC CAG ACG CTC ACA GAC TGG CTT C (5/6-TAMRA).

For the amplification of mouse guanine nucleotide binding protein, alpha 1 1 (Gna1 1 ) (SEQ ID NO: 7): 5'- GCG ACA AAA TCA TCT ACT CCC ACT -3'; mouse Gna1 1 reverse primer (SEQ ID NO: 8): 5'- CTG CGA ACA CAA AGC GGA T-3'; Taqman probe (SEQ ID NO: 9): (5/6-FAM) CAC ATG TGC CAC CGA CAC CGA GA (5/6-TAMRA).

For the amplification of mouse prostate tumor over expressed gene 1 (Ptovl ) (SEQ ID NO: 10): 5'- CCA CCC TCG TGC CAC TG -3'; mouse Ptovl reverse primer (SEQ ID NO: 1 1 ): 5'- TTC AGA GTC TCC ATG TCC TTA GTG A -3'; Taqman probe (SEQ ID NO: 12): (5/6-FAM) TCC GGA ATT CAC GCC TGG TAC AGT TC (5/6-TAMRA).

For the amplification of mouse delta-like 1 (Drosophila) (DII1 ) (SEQ ID NO: 13): 5'- GAC CTT CTT TCG CGT ATG CCT -3'; mouse Dill reverse primer (SEQ ID NO: 14): 5'- CGT AGG TGC AGG GTG GCT -3'; Taqman probe (SEQ ID NO: 15): (5/6-FAM) AAG CAC TAC CAG GCC AGC GTG TCA C (5/6-TAMRA) .

For the amplification of mouse solute carrier family 1 1 , member 1 (Slc1 1 a1 ) (SEQ ID NO: 16): 5'- CGC CCA CGG AGC CA -3'; mouse Slc1 1 a1 reverse primer (SEQ ID NO: 17): 5'- CTC GTT AGG GAG CCC ATA TAA GAA G -3'; Taqman probe (SEQ ID NO: 18): (5/6-FAM) TCC TGA CCC ACA GCT CCC ACA AGC G (5/6-TAMRA).

For the amplification of mouse solute carrier family 1 1 , member 2 (Sid 1 a2) (SEQ ID NO: 19): 5'- CCT TTG CTC TCA TAC CCA TCC T -3'; mouse Slc1 1 a2 reverse primer (SEQ ID NO: 20): 5'- TCC ATT GGA AAA CTC ACT CAT CA -3'; Taqman probe (SEQ ID NO: 21 ): (5/6-FAM) ACG TTC ACA AGC CTG CGG CCA (5/6-TAMRA).

For the amplification of mouse osteoblast specific factor 2 (fasciclin l-like) (Osf2-pending) (SEQ ID NO: 22): 5'- TCA CTG TGA ACT GTG CTC GAG TC -3'; mouse Osf2-pending reverse primer (SEQ ID NO: 23) : 5'- ACG GTC AAT GAC ATG GAC GA -3'; Taqman probe (SEQ ID NO: 24): (5/6-FAM) TCC ATG GGA ACC AGA TTG CCA CAA A (5/6-TAMRA).

In the figures the relative RNA-expression is shown on the Y-axis. In Figures 4, 8A-C, 13, 17, 24, 31A-E, and 35A-C, the tissues tested are given on the X-axis. "WAT" refers to white adipose tissue, "BAT" refers to brown adipose tissue. In Figure 8D, 31 F, and 35D, the X-axis represents the time axis. "dO" refers to day 0 (start of the experiment), "d2" - "d 10" refers to day 2 - day 10 of adipocyte differentiation.

As shown in Figure 4A, real time PCR (Taqman) analysis of the expression of the diacylglycerol kinase, epsilon (Dgke) RNA in mammalian (mouse) tissues revealed that Dgke is expressed in different mammalian tissues, showing highest level of expression in hypothalamus and brain and higher levels in further tissues, e.g. heart, lung, WAT, BAT, muscle and spleen. As shown in Figure 4B Dgke is nearly three fold up regulated in the hypothalamus of ob /ob mice and nearly two fold up regulated in BAT, muscle, liver and pancreas of fasted animals. Furthermore Dgke is more than two fold up regulated in BAT of high fat diet mice as shown in Figure 4C.

The regulated expression of Dgke in the hypothalamus of ob/ob mice and in the BAT of mice fed with a high fat diet shows that this gene plays a central role in energy homeostasis. This is supported by the up regulation of Dgke in diverse metabolic active tissues of fasted animals.

As shown in Figure 8A, real time PCR (Taqman) analysis of the expression of the Synaptojanin 1 RNA in mammalian (mouse) tissues revealed that Synaptojanin 1 is expressed in different mammalian tissues, showing highest level of expression in brain and hypothalamus and on lower but still robust levels in further tissues, e.g. heart, lung, WAT, BAT, muscle, liver, kidney and spleen. As shown in Figure 8B Synaptojanin 1 is more than three fold up regulated in the WAT of ob /ob mice. Furthermore Synaptojanin 1 is more than two fold up regulated in WAT of high fat diet mice as shown in Figure 8C.

The up regulation of Synaptojanin 1 in the WAT of both, mice fed with a high fat diet and geneticaly obese mice, shows that this gene plays a central role in energy homeostasis. This is supported by the down regulation of Synaptojanin 1 during adipogenesis as shown in Figure 8D.

As shown in Figure 13A, real time PCR (Taqman) analysis of the expression of the guanine nucleotide binding protein, alpha 1 1 (Gna1 1 ) RNA in mammalian (mouse) tissues revealed that Gna1 1 is expressed in different mammalian tissues, showing highest level of expression in small intestine, colon and WAT, and higher levels in further tissues, e.g. BAT, muscle, liver, hypothalamus and brain. As shown in Figure 1 3B Gna1 1 is nearly two fold up regulated in BAT and liver of fasted animals. Gna 1 1 is nearly three fold up regulated in liver and hypothalamus and more than two fold down regulated in WAT of ob /ob mice. Furthermore Gna1 1 is more than two fold down regulated in WAT and more than two fold up regulated in the muscle of high fat diet mice as shown in Figure 13C.

The regulated expression of Gna1 1 in the hypothalamus and liver of ob/ob mice and in the BAT of fasted animals shows that this gene plays a central role in energy homeostasis. This is supported by the down regulation of Gna1 1 in the WAT of mice fed with a high fat diet and genetically obese mice, two animal models used to study metabolic disorders.

As shown in Figure 17A, real time PCR (Taqman) analysis of the expression of the prostate tumor over expressed gene 1 (Ptovl ) RNA in mammalian (mouse) tissues revealed that Ptovl is expressed in different mammalian tissues, showing highest level of expression in brain, hypothalamus and WAT, and higher levels in further tissues, e.g. heart, BAT, muscle, lung and kidney. As shown in Figure 17B Ptovl is more than three fold down regulated in WAT of fasted animals and ob /ob mice.

The expression of Ptovl in diverse metabolic active tissues together with the down regulation in the WAT of fasted animals and ob/ob mice shows that this gene plays a central role in energy homeostasis.

As shown in Figure 24A, real time PCR (Taqman) analysis of the expression of the mouse delta-like 1 (Drosophila) (DII1 ) RNA in mammalian (mouse) tissues revealed that DIM is expressed in different mammalian tissues, showing highest level of expression in spleen, lung, small intestine and WAT and on higher levels in further tissues, e.g. hypothalamus, brain, heart, kidney and colon. As shown in Figure 24B DII1 is more than two fold up regulated in the BAT of ob /ob mice and five fold down regulated in pancreas of fasted animals and ob /ob mice. Furthermore DIM is more than two fold up regulated in muscle and liver of high fat diet mice as shown in Figure 24C.

The regulated expression of DM in different metabolic active tissues of animal models used to study metabolic disorders, shows that this gene plays a central role in energy homeostasis.

As shown in Figure 31 A, real time PCR (Taqman) analysis of the expression of the solute carrier family 1 1 , member 1 (Slc1 1 a1 ) RNA in mammalian (mouse) tissues revealed that Slc1 1 a1 is expressed in different mammalian tissues, showing highest level of expression in spleen, WAT and lung, and on lower but still robust levels in further tissues, e.g. BAT, muscle, liver and heart. As shown in Figure 31 B Slc1 1a1 is strongly up regulated in the WAT of ob/ob mice. Slc1 1 a1 expression is more than two fold up regulated in hypothalamus and liver, and more than three fold up regulated in muscle and lung of ob/ob mice. Slc1 1 a1 shows up regulation in BAT, muscle, pancreas and spleen of fasted animals. Furthermore Slc1 1 a1 is strongly regulated in WAT and more than three fold up regulated in muscle of high fat diet mice as shown in Figure 31 C.

As shown in Figure 31 D solute carrier family 1 1 , member 2 (Slc1 1 a2) is highly expressed in small intestine, kidney and WAT, and on lower but robust levels in further tissue, e.g. brain, hypothalamus, lung, heart, BAT, muscle, liver, kidney and spleen of wild type animals. As shown in Figure 31 E Slc1 1 a2 is more than two fold up regulated in the hypothalamus of ob/ob mice. As shown in Figure 31 F Slc1 1 a2 is down regulated during adipogenesis.

The strong up regulation of Slc1 1 a1 in the WAT of high fat diet mice and genetically obese mice, shows that this gene plays a central role in energy homeostasis. This is supported by the regulation of Slc1 1 a1 in different metabolic active tissue of ob/ob mice and fasted animals, two animal models used to study metabolic disorders.

The regulated expression of Sid 1 a2 in the hypothalamus of ob/ob mice together with the down regulation during the differentiation from preadipocytes to mature adipocytes, shows that this gene plays a central role in energy homeostasis.

As shown in Figure 35A osteoblast specific factor 2 (fasciclin l-like) (Osf2-pending) is highly expressed in lung, colon and BAT, and on lower but robust levels in further tissue, e.g. WAT, heart, muscle, liver, kidney and spleen of wild type animals. As shown in Figure 35B Osf2-pending is more than six fold up regulated in WAT and muscle of ob/ob mice and more than three fold up regulated in WAT and muscle of high fat diet mice (Figure 35C). Osf2-pending is nearly three fold up regulated in liver and BAT of ob/ob mice and more than two fold up regulated in WAT, muscle and pancreas of fasted animals as shown in Figure 35B. Furthermore Osf2-pending is more than two fold down regulated in colon of fasted animals and ob/ob mice and in spleen of fasted animals and high fat diet mice as shown in Figures 35B and 35C.

The regulated expression of Osf2-pending in different metabolic active tissues of diverse animal models used to study metabolic disorders, shows that this gene plays a central role in energy homeostasis. This is supported by the down regulation of Osf2-pending during adipogenesis as shown in Figure 35D.

Example 6. Analysis of the differential expression of transcripts of the proteins of the invention in human tissues

RNA preparation from human primary adipose tissues was done as described in Example 5. The hybridization and scanning was performed as described in the manufactures manual (see Affymetrix Technical Manual, 2002, obtained from Affmetrix, Santa Clara, USA).

Figures 9 and 36 show an analysis of primary human abdominal adipocycte differentiation using Affymetrix GeneChips. The expression analysis of the human synaptojanin homologs (SYNJ1 , SYNJ2) and the fasciclin 1 -homolog OSF-2 genes clearly shows differential expression of human synaptojanin 1 (SYNJ1 ), synaptojanin 1 (SYNJ2), and osteoblast specific factor 2 (OSF-2) genes in adipocytes. Several independent experiments were done. The experiments further show that the SYNJ1 , SYNJ2, and OSF-2 transcripts (see Figures 9A, 9B, and 36) are most abundant at day 0 compared to day 12 during differentiation. The X-axis represents the time axis, shown are day 0 and day 12 of adipocyte differentiation. The Y-axis represents the fluorescent intensity.

Thus, the SYNJ1 , SYNJ2, and OSF-2 proteins have to be significantly decreased in order for the preadipocyctes to differentiate into mature adipocycte. Therefore, the SYNJ1 , SYNJ2, and OSF-2 proteins in preadipocyctes have the potential to inhibit adipose differentiation at a very early stage. Therefore, SYNJ1 , SYNJ2, and OSF-2 proteins might play an essential role in the regulation of human metabolism, in particular in the regulation of adipogenesis and thus it might play an essential role in obesity, diabetes, and/or metabolic syndrome.

For the purpose of the present invention, it will understood by the person having average skill in the art that any combination of any feature mentioned throughout the specification is explicitly disclosed herewith.

Claims

1 . A pharmaceutical composition comprising a Dgk epsilon, synaptojanin, G alpha 49B, CG13609, Rab8, Delta, Nup214,

Malvolio, or Fasciclin 1 homologous nucleic acid molecule or a polypeptide encoded thereby and/or a functional fragment thereof or a modulator/effector of said nucleic acid molecule and/or a polypeptide encoded thereby together with pharmaceutically acceptable carriers, diluents and/or additives.

2. The composition of claim 1 , wherein the nucleic acid molecule is a vertebrate or insect Dgk epsilon, synaptojanin, G alpha 49B, CG13609, Rab8, Delta, Nup214, Malvolio, or Fasciclin 1 nucleic acid, particulary encoding a human protein as described in Table 1 , and/or a nucleic molecule which is complementary thereto or a functional fragment thereof or a variant thereof.

3. The composition of claim 1 or 2, wherein said nucleic acid molecule is selected from the group of

(a) a nucleic acid molecule encoding a polypeptide as shown in Table 1 ;

(b) a nucleic acid molecule which comprises or is the nucleic acid molecule as shown in Table 1 ; (c) a nucleic acid molecule degenerate as a result of the genetic code to the nucleic acid sequences as defined in (a) or (b);

(d) a nucleic acid molecule that hybridizes at 50°C in a solution containing 1 x SSC and 0.1 % SDS to a nucleic acid molecule as defined in claim 2 and/or a nucleic acid molecule which is complementary thereto;

(e) a nucleic acid molecule that encodes a polypeptide which is at least 85%, preferably at least 90%, more preferably at least 95%, more preferably at least 98% and up to 99,6% identical to a human protein as described in Table 1 or as defined in claim 2; and (f) a nucleic acid molecule that differs from the nucleic acid molecule of (a) to (e) by mutation and wherein said mutation causes an alteration, deletion, duplication or premature stop in the encoded polypeptide.

4. The composition of any one of claims 1-3, wherein the nucleic acid molecule is a DNA molecule, particularly a cDNA or a genomic DNA.

5. The composition of any one of claims 1-4, wherein said nucleic acid encodes a polypeptide contributing to regulating the energy homeostasis and/or the metabolism of triglycerides.

6. The composition of any one of claims 1 -5, wherein said nucleic acid molecule is a recombinant nucleic acid molecule.

7. The composition of any one of claims 1 -6, wherein the nucleic acid molecule is a vector, particularly an expression vector.

8. The composition of any one of claims 1 -5, wherein the polypeptide is a recombinant polypeptide.

9. The composition of claim 8, wherein said recombinant polypeptide is a fusion polypeptide.

10. The composition of any one of claims 1 -7, wherein said nucleic acid molecule is selected from hybridization probes, primers and anti-sense oligonucleotides.

1 1 . The composition of any one of claims 1 -10 which is a diagnostic composition.

12. The composition of any one of claims 1 -10 which is a therapeutic composition.

13. The composition of any one of claims 1 -12 for the manufacture of an agent for detecting and/or verifying, for the treatment, alleviation and/or prevention of metabolic diseases or dysfunctions, including metabolic syndrome, obesity, and/or diabetes, as well as related disorders such as eating disorder, cachexia, hypertension, coronary heart disease, hypercholesterolemia, dyslipidemia, osteoarthritis, or gallstones, liver fibrosis, or gallstones, in cells, cell masses, organs and/or subjects.

14. Use of a nucleic acid molecule of the as described in Table 1 , particular of a nucleic acid molecule according to claim 3 (a), (b), or (c), or a polypeptide encoded thereby or a functional fragment or a variant of said nucleic acid molecule or said polypeptide and/or a modulator/effector of said nucleic acid molecule or polypeptide for the manufacture of a medicament for the treatment of obesity, diabetes, and/or metabolic syndrome for controlling the function of a gene and/or a gene product which is influenced and/or modified by a Dgk epsilon, synaptojanin, G alpha 49B, CG1 3609, Rab8, Delta, Nup214, Malvolio, or Fasciclin 1 homologous polypeptide, particularly by a polypeptide according to claim 3.

1 5. Use of the nucleic acid molecule as described in Table 1 , particularly of a nucleic acid molecule according to claim 3 (a), (b), or (c), or a polypeptide encoded thereby or a fragment or a variant of said nucleic acid molecule or said polypeptide or a modulator/effector of said nucleic acid molecule or said polypeptide for identifying substances capable of interacting with a polypeptide, particularly with a polypeptide according to claim 3.

16. A non-human transgenic animal exhibiting a modified expression of a Dgk epsilon, synaptojanin, G alpha 49B, CG 13609, Rab8, Delta,

Nup214, Malvolio, or Fasciclin 1 homologous polypeptide, particularly of a polypeptide according to claim 3.

17. The animal of claim 16, wherein the expression of the Dgk epsilon, synaptojanin, G alpha 49B, CG 13609, Rab8, Delta, Nup214,

Malvolio, or Fasciclin 1 homologous polypeptide, particularly of a polypeptide according to claim 3, is increased and/or reduced.

18. A recombinant host cell exhibiting a modified expression of a Dgk epsilon, synaptojanin, G alpha 49B, CG 13609, Rab8, Delta,

Nup214, Malvolio, or Fasciclin 1 homologous polypeptide, particularly with a polypeptide according to claim 3.

19. The cell of claim 18 which is a human cell.

20. A method of identifying a (poly)peptide involved in the regulation of energy homeostasis and/or metabolism of triglycerides in a mammal comprising the steps of

(a) contacting a collection of (poly)peptides with a Dgk epsilon, synaptojanin, G alpha 49B, CG1 3609, Rab8, Delta, Nup214,

Malvolio, or Fasciclin 1 homologous polypeptide, particularly with a polypeptide according to claim 3, or a functional fragment thereof under conditions that allow binding of said (poly)peptides; (b) removing (poly)peptides which do not bind and (c) identifying (poly)peptides that bind to said Dgk epsilon, synaptojanin, G alpha 49B, CG 13609, Rab8, Delta, Nup214, Malvolio, or Fasciclin 1 homologous polypeptide.

21 . A method of screening for an agent which modulates/effects the interaction of a Dgk epsilon, synaptojanin, G alpha 49B, CG 1 3609, Rab8, Delta, Nup214, Malvolio, or Fasciclin 1 homologous polypeptide, particularly of a polypeptide according to claim 3, with a binding target, comprising the steps of (a) incubating a mixture comprising

(aa) a Dgk epsilon, synaptojanin, G alpha 49B, CG 1 3609,

Rab8, Delta, Nup214, Malvolio, or Fasciclin 1 homologous polypeptide, particularly a polypeptide according to claim 3, or a functional fragment thereof; (ab) a binding target/agent of said polypeptide or functional fragment thereof; and (ac) a candidate agent under conditions whereby said polypeptide or functional fragment thereof specifically binds to said binding target/agent at a reference affinity;

(b) detecting the binding affinity of said polypeptide or functional fragment thereof to said binding target to determine an affinity for the agent; and

(c) determining a difference between affinity for the agent and the reference affinity.

22. A method for screening for an agent, which modulates/effects the activity of a Dgk epsilon, synaptojanin, G alpha 49B, CG 1 3609, Rab8, Delta, Nup214, Malvolio, or Fasciclin 1 homologous polypeptide, particularly of a polypeptide according to claim 3, comprising the steps of (a) incubating a mixture comprising (aa) said polypeptide or a functional fragment thereof;

(ab) a candidate agent under conditions whereby said polypeptide or functional fragment thereof has a reference activity;

(b) detecting the activity of said polypeptide or functional fragment thereof to determine an activity in presence of the agent; and

(c) determining a difference between the activity in the presence of the agent and the reference activity.

23. A method of producing a composition comprising the (poly)peptide identified by the method of claim 20 or the agent identified by the method of claim 21 or 22 with a pharmaceutically acceptable carrier, diluent and/or additive.

24. The method of claim 23 wherein said composition is a pharmaceutical composition for preventing, alleviating or treating of metabolic diseases or dysfunctions, including metabolic syndrome, obesity, and/or diabetes as well as related disorders such as eating disorder, cachexia, hypertension, coronary heart disease, hypercholesterolemia, dyslipidemia, osteoarthritis, gallstones, or liver fibrosis.

25. Use of a (poly)peptide as identified by the method of claim 20 or of an agent as identified by the method of claim 21 or 22 for the preparation of a pharmaceutical composition for the treatment, alleviation and/or prevention of metabolic diseases or dysfunctions, including metabolic syndrome, obesity, and/or diabetes as well as related disorders such as eating disorder, cachexia, hypertension, coronary heart disease, hypercholesterolemia, dyslipidemia, osteoarthritis, gallstones or liver fibrosis.

26. Use of a nucleic acid molecule as defined in any of claims 1 -6 or 10 for the preparation of a medicament for the treatment, alleviation and/or prevention of metabolic diseases or dysfunctions, including obesity, diabetes, and/or metabolic syndrome, as well as related disorders such as eating disorder, cachexia, hypertension, coronary heart disease, hypercholesterolemia, dyslipidemia, osteoarthritis, gallstones, or liver fibrosis.

27. Use of a polypeptide as defined in any one of claims 1 to 6, 8 or 9 for the preparation of a medicament for the treatment, alleviation and/or prevention of metabolic diseases or dysfunctions, including obesity, diabetes, and/or metabolic syndrome, as well as related disorders such as eating disorder, cachexia, hypertension, coronary heart disease, hypercholesterolemia, dyslipidemia, osteoarthritis, gallstones, or liver fibrosis.

28. Use of a vector as defined in claim 7 or the preparation of a medicament for the treatment, alleviation and/or prevention of metabolic diseases or dysfunctions, including obesity, diabetes, and/or metabolic syndrome, as well as related disorders such as eating disorder, cachexia, hypertension, coronary heart disease, hypercholesterolemia, dyslipidemia, osteoarthritis, or gallstones, or liver fibrosis.

29. Use of a host cell as defined in claim 18 or 1 9 for the preparation of a medicament for the treatment, alleviation and/or prevention of metabolic diseases or dysfunctions, including obesity, diabetes, and/or metabolic syndrome, as well as related disorders such as eating disorder, cachexia, hypertension, coronary heart disease, hypercholesterolemia, dyslipidemia, osteoarthritis, gallstones, or liver fibrosis.

0. Use of a Dgk epsilon, synaptojanin, G alpha 49B, CG 13609, Rab8, Delta, Nup214, Malvolio, or Fasciclin 1 homologous nucleic acid molecule or of a functional fragment thereof for the production of a non-human transgenic animal which over- or under-expresses the Dgk epsilon, synaptojanin, G alpha 49B, CG13609, Rab8, Delta,

Nup214, Malvolio, or Fasciclin 1 homologous gene product.

1 . Kit comprising at least one of

(a) a Dgk epsilon, synaptojanin, G alpha 49B, CG 13609, Rab8, Delta, Nup214, Malvolio, or Fasciclin 1 homologous nucleic acid molecule or a functional fragment thereof;

(b) a Dgk epsilon, synaptojanin, G alpha 49B, CG 13609, Rab8, Delta, Nup214, Malvolio, or Fasciclin 1 homologous amino acid molecule or a functional fragment thereof; (c) a vector comprising the nucleic acid of (a);

(d) a host cell comprising the nucleic acid of (a) or the vector of (O;

(e) a polypeptide encoded by the nucleic acid of (a);

(f) a fusion polypeptide encoded by the nucleic acid of (a); (g) an antibody, an aptamer or another modulator/effector of the nucleic acid of (a) or the polypeptide of (b), (e), or (f) and (h) an anti-sense oligonucleotide of the nucleic acid of (a) .