WO2008032911A1

WO2008032911A1 - Cell surface expression vector of myosyatin and microorganisms transformed therewith

Info

Publication number: WO2008032911A1
Application number: PCT/KR2007/000856
Authority: WO
Inventors: Chul Joong Kim; Moon-Hee Sung; Seung-Pyo Hong; Jong-Soo Lee; Il Han Lee; Long Chun Xu; Jong-Taik Kim; Yoon-Ho Choi
Original assignee: Bioleaders Corporation
Priority date: 2006-09-14
Filing date: 2007-02-16
Publication date: 2008-03-20
Also published as: KR20070031248A; KR100872042B1

Abstract

The present invention relates to a vector expressing myostatin mature proteins, a recombinant microorganism transformed with the vector, and a feedstuff additive or a vaccine containing the myostatin mature proteins expressed on the cell surface thereof, and more particularly, to a cell surface expression vector containing a polynucleotide encoding a myostatin mature protein and a gene encoding a poly-gamma-glutamate synthetase complex which induces surface expression in a microorganism, a microorganism transformed with the vector, and a feedstuff additive or a vaccine, containing the myostatin mature proteins prepared by culturing the transformed microorganism, as an effective ingredient. The inventive feedstuff additive or vaccine containing the myostatin mature proteins expressed on a cell surface, as an effective ingredient, can be used for preventing and treating muscle-wasting diseases and degenerative diseases such as muscular dystrophy, muscular atrophy and the like, as well as increasing and controlling muscle growth of livestock and poultry. In addition, the transformed strain onserved in the knockout mice, shows the same effect even if the strain itself after culturing is directly used, and thus it is very economical.

Description

CELL SURFACE EXPRESSION VECTOR OF MYOSYATIN AND MICROORGANISMS TRANSFORMED THEREWITH

TECHNICAL FIELD

The present invention relates to a vector expressing myostatin mature proteins, a microorganism transformed with the vector, and a feedstuff additive or a vaccine containing the myostatin mature proteins expressed on the cell surface thereof, and more particularly, to a cell surface expression vector containing a polynucleotide encoding a myostatin mature protein and a gene encoding a poly-gamma-glutamate synthetase complex which induces surface expression in a microorganism, a recombinant microorganism transformed with the vector, and a feedstuff additive or a vaccine, containing the myostatin mature proteins prepared by culturing the recombinant microorganism, as an effective ingredient.

BACKGROUND ART

GDF-8(Growth Differentiation Factor-8) or myostatin as a growth controlling factor, which selectively negative regulates skeketal muscle growth, are discovered in 1997 (McPherron et ai, Nature, 387:83, 1997). A research team, which discovered myostatin, has announced that two high quality cow breeds due to their high muscular mass and tender meat, i.e., Belgian blue and Piedmontese, comprise mutation in gene encoding myostatin, which results in muscle development (McPherron and Lee, Proc. Natl Acad. Sci. USA., 94:12457, 1997), and reported that double-muscle animals of these breeds have average muscle mass increased by 20-25% based on that of ordinary animals. Experimetally, myostatin-knockout mice also showed significant increases in skeletal muscle mass, and muscles isolated from myostatin-negative mice were about 2- to 3- fold heavier than muscles isolated from wild mice. It has been reported that knockout mice have about 35% higher total body weight than that of wild mice and myostatin-deficient mice have more than 80% muscle fibers compared to normal mice, and the increment of skeletal muscle observed in the knockout mice, is caused by abnormal growth of muscle fibers as well as an increase in the number of muscle fibers.

Myostatin as a growth controlling factor, which selectively negative regulates skeletal muscle growth, belongs to TGF-α(transforming growth factor-α) super family, is composed of 375 amino acid precursors, and has the same C-terminal fragments of about 109 amino acid residues in mice, rats, human, swine, fowl and turkey and only 3 amino acid residues in the C-terminal region thereof are not the same in monkeys, cows, and sheep. The C-terminal regions are expected to include physiologically active portion of myostatin. Myostatin has shown a high degree of conservation along evolution in various species, which implies that myostatin is an essential factor in biological muscle control.

Myostatin expression is limited to skeletal muscle and it is expressed at low levels in adipose tissue. It seems that myostatin functions as a negative regulator specific to skeletal muscle growth, but the physiological role of myostatin in an adult individual is not known. Altough studies on the physiological role of myostatin have been focused on abnormal growth after muscle damage or its regeneration ability, it is also known that myostatin inhibits adipose tissue growth. However, it has not been known yet whether myostatin acts locally or systemically to regulate animal growth.

Recently, various studies are being conducted using myostatin exerting the role for negative regulation of skeletal muscle growth. Representative studies thereof include the development of therapeutic agents for treatment of human diseases using to apply to treatment of deseases including muscle-wasting diseases such as muscular dystrophy or muscular atrophy, or muscle loss caused by AIDS, cancer and the like, and an attempt to apply to a feedstuff additive for livestock to produce high quality meat. Moreover, since, when myostatin is developed as supplement additives for muscle enhancement, it can inhibit body fat accumulation due to an increase in the amount of muscle, it is expected to be effective for those who are on a diet, and thus, studies thereof are also being conducted.

Two representative studies on a method for inducing muscle growth by inhibiting the function of myostatin protein, are being conducted. One is to discover and use various proteins (follastatin, mutant activin type II receptor, myostatin propeptide, etc.), which inhibit myostatin activity to suppress its fuction, and the other is to produce antibodies against myostatin polypeptide by animal immunization using myostatin polypeptide, a subsequence thereof, and mutant subsequences. It was reported that the production of antibodies against myostatin immunogens in vertebrate animals results in a reduction in endogenious myostatin activity, thus showing biological effects such as body weight gain, increased muscle mass, an increase in the number of muscle cells, an increase in muscle cell size, a decrease in the amount of body fat, an increase in muscular strength and the like. However, most of the studies are conducted by artificially synthesizing myostatin or the subsequence thereof, or preparing by isolation and purification after expressing them in Escherichia coli, which results in economic inefficiency and thus, it is difficult to apply them to industrial applications.

In livestock industry, various breeding programs to enhance the growth rate of animals by increasing the efficiency of feedstuff additives, are being developed and improved. Among them, medical approaches include methods of administering antibiotics or antibiotic-like compounds to breeding animals, or administering hormones such as growth hormones to them. However, the administration of antibiotics or antibiotic-like compounds to breeding animals is banned, since it can cause a problem of inducing antibiotic cross-resistance. Additionally, in the case of administration of growth hormone to breeding animals, it is disadvantageous in that it costs a lot, short period of treatment should be repeated because of a short half- time of growth hormone, and growth hormone remaining in meat obtained from animals treated therewith may cause health problems in humans.

Bacause of the difficulties in the medical approaches, various breeding programs, to enhance the growth rate of animals using after methods for increasing the efficiency of feedstuff additives, are being continuously developed.

Technology of expressing by attaching a desired protein to the cellular surface of microorganisms is referred to as a cell surface display technology. The cell surface display technology is to express a foreign protein on the cellular surface using the surface protein of microorganisms, such as bacteria or yeasts, as a surface anchoring motif, and is used in a wide range of applications, including the production of recombinant live vaccines, the construction and screening of peptide/antibody libraries, whole cell absorbents and bioconversion catalysts. The application range of this technology is determined depending on what kind of protein is expressed on the cell surface, thus, the industrial application potentiality of the cell surface display technology can be said to be significant.

For successful cell surface display, a surface anchoring motif is most important. How effectively a motif capable of expressing a foreign protein on the cell surface is selected and developed is the core of this technology. Accordingly, a surface anchoring motif with the following properties should be selected. First, it should have a secretory signal helping the foreign protein to pass through the inner cell membrane, and to reach to the cell surface. Second, it should have a target signal helping the foreign protein to be stably attached to the outer cell membrane surface. Third, it should be expressed on the cell surface at large amounts but has little or no effect on the growth of cells. Fourth, it should be stably expressed regardless of the protein size, without causing a change in the three-dimensional structure of the foreign protein. However, a surface anchoring motif meeting all the above requirements have not yet been developed.

Cell surface anchoring motifs, which have been known and used till now, are broadly classified into four kinds, i.e., outer membrane proteins, lipoproteins, secretory proteins, and surface organ proteins such as flagella proteins. In the case of gram-negative bacteria, proteins present on the outer cell membrane, such as LamB, PhoE (Charbit et al, J. Immunol., 139:1658, 1987; Agterberg et al, Vaccine, 8:85, 1990) and OmpA, were mainly used. Moreover, lipoproteins, such as TraT (Felici et al, J. MoI. Biol, 222:301, 1991), PAL (peptidoglycan associated lipoprotein) (Fuchs et al, Bio/Technology, 9:1369, 1991) and Lpp (Francisco et al, Proc. Natl Acad. ScL USA., 489:2713, 1992), were also used. Furthermore, the expression of foreign proteins was also attempted using FimA, a fimbriae protein such as the FimH adhesion of type 1 fimbriae (Hedegaard et al, Gene, 85:115, 1989), or a pili protein such as a PapA pilu subunit as surface anchoring motifs. In addition, it was reported that an ice nucleation protein (Jung et al, Nat. Biotechnol, 16:576, 1998; Jung et al, Enzyme Microb. Technol, 22:348, 1998; Lee et al, Nat. Biotechnol, 18:645, 2000), pullulanase of Klebsiella oxytoca (Kornacker et al, MoI Microbiol, 4:1101, 1990), IgA protease of Neisseria (Klauser et al, EMBO J., 9:1991, 1990), E. coli adhesion AIDA-I, VirG protein of Shigella, a fusion protein of Lpp and OmpA, can be used as surface anchoring motifs. In the case of using Gram-positive bacteria, there is a report that a malaria antigen was effectively expressed using Staphylococcus aureus-άeήved protein A and FnBPB protein, as surface anchoring motifs. In addition, it was reported that the surface coat protein of lactic acid bacteria was used in surface expression and a Streptococcus pyogenes- derived M6 protein (Medaglini, D et al, Proc. Natl. Acad. ScL USA., 92:6868, 1995), S-layer protein EAl of Bacillus anthracis, and surface protein of Gram- positive bacteria such as Bacillus subtilis CotB, etc., were used as surface anchoring motifs.

In addition, the present inventors already developed a novel vector effectively 5 expressing a foreign protein on the surface of microorganisms using apgsBCA gene encoding a Bacillus sp. strain-derived poly-gamma-glutamate synthetase complex as a new surface anchoring motif, as well as a method for expressing a large amount of foreign protein on the surface of microorganisms transformed with the vector (WO 2003/14360). Many studies were performed in an attempt to stably express 0 the antigen or epitope of pathogenic organisms in bacteria, where mass production is possible, by genetic engineering techniques using the above-described surface anchoring motifs. It was reported that, particularly when a foreign immunogen expressed on the surface of non-pathogenic bacteria is orally administered alive, a more lasting and strong immune response than that of the prior vaccine using the5 prior attenuated pathogenic bacteria or viruses, can be induced. This induction of the immune reaction is known to be because the surface structures of the bacteria act as adjuvants increasing the antigenicity of the surface-expressed foreign protein, and an in vivo immune response to the live bacteria occurs. The development of a recombinant live vaccine of non-pathogenic bacteria using this surface expression o system is noticeable.

Accordingly, the present inventors have made extensive efforts to develop a method for effectively expressing myostatin on the surface of microorganisms, and as a result, abundantly expressed myostatin mature proteins on the surface of5 microorganisms with food safety guaranteed, such as lactic acid bacteria, using pgsBCA genes encoding a Bacillus sp. strain-derived poly-gamma-glutamate synthetase complex as a surface anchoring motif and found that antibodies against myostatin in blood are produced and the body weight of animal subjects is increased by orally administering the microorganisms having abundant myostatin mature proteins expressed on the surface thereof, thereby completing the present invention SUMMARY OF THE INVENTION

One object of the present invention is to provide a surface expression vector comprising a gene encoding a poly-gamma-glutamate synthetase complex and a polynucleotide encoding a mature domain of myostatin protein, and a recombinant microorganism transformed with the expression vector.

Another object of the present invention is to provide a method for preparing a microorganism expressing myostatin mature proteins on its surface.

Still another object of the present invention is to provide a feedstuff additive or a vaccine containing the myostatin mature proteins expressed on the cell surface, which is produced by said method, as an effective antibody.

To achieve the above object, the present invention provides a cell surface expression vector comprising at least one gene selected from the group consisting of pgsB, pgsC and pgsA genes, which encode a poly-gamma-glutamate synthetase complex, and a polynucleotide encoding a mature domain of myostatin protein, and a recombinant microorganism transformed with the expression vector.

The present invention also provides a method for preparing a microorganism having myostatin mature proteins expressed on the surface thereof, the method comprising the steps of expressing the myostatin mature proteins on the surface of the microorganism by culturing the transformed microorganism; and collecting the microorganism having the myostatin mature proteins expressed on the surface thereof.

In addition, the present invention provides a feedstuff additive for promoting animal muscle growth and improving animal weight gain, which contains the microorganism prepared by the method to have the myostatin mature proteins expressed on the surface thereof and, as an effective ingredient.

Moreover, the present invention provides a vaccine for promoting animal muscle growth and improving animal weight gain, which contains the myostatin mature proteins prepared by the method to be expressed on the cell surface, as an effective antibody.

The present invention also provides a method for increasing animal body weight, muscle mass, the number of muscle cells and/or muscle cell size, or decreasing body fat, the method comprises administering the feedstuff additive or the vaccine are administered to animals.

Moreover, the present invention provides a vaccine for preventing and/or treating a muscle-wasting diseases and degenerative diseases, which contains the myostatin mature proteins prepared by the method to be expressed on the cell surface, as an effective antibody.

The above and other objects, features and embodiments of the present invention will be more clearly understood from the following detailed description and accompanying claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a genetic map of surface expression vector, pBT:pgsA-CMyom expressing chicken myostatin mature proteins, according to the present invention.

FIG. 2 shows the results of Western blot analysis, (a) is the result obtained by performing Western blot analysis using pgsA-specific antibodies after fractionating cells obtained by culturing lactic acid bacteria transformd with the inventive pBT:pgsA-CMyom, and (b) is the result ontained by performing Western blot analysis using myoatstin mature protein antigen-specific antibodies.

FIG. 3 shows IgG antibody titers against myostatin mature antigens in the serum of mice orally administered with Lactobacillus casei strain, which has been transformed with the inventive pBT:pgsA-CMyom to have myostatin mature proteins expressed on the surface thereof, by ELISA(Enzyme-linked immunosorbent assay).

FIG. 4 shows the results of body weight changes in mice orally administered with Lactobacillus casei strain which has been transformed with the inventive pBT:pgsA-CMyom to have myostatin mature proteins expressed on the surface thereof.

FIG. 5 shows IgG antibody titers against myostatin mature antigens in the serum of chicks orally administered with Lactobacillus casei strain through feed, which has been transformed with the inventive pBT:pgsA-CMyom to have myostatin mature proteins expressed on the surface thereof, by ELISA(Enzyme-linked immunosorbent assay).

FIG. 6 shows the results of body weight changes in chicks orally administered with Lactobacillus casei strain through feed, which has been transformed with the inventive pBT:pgsA-CMyom to have myostatin mature proteins expressed on the surface thereof.

FIG. 7 shows feeds efficiency in chicks orally administered with Lactobacillus casei strain through feed, which has been transformed with the inventive pBT:pgsA-CMyom to have myostatin mature proteins expressed on the surface thereof. FIG. 8 shows the results of Western blot analysis using pgsA-specific antibodies(a) and myoatstin mature protein antigen-specific antibodies(b) after fractionating cells obtained by culturing lactic acid bacteria transformd with the inventive pBT:pgsA- CMyom.

FIG. 9 shows the results of body weight changes in swines orally administered with Lactobacillus casei strain through feed, which has been transformed with the inventive pBT:pgsA-CMyom to have myostatin mature proteins expressed on the surface thereof.

FIG. 10 is a genetic map of surface expression vector pBT:pgsA-BMyom expressing bovine myostatin mature proteins, according to the present invention.

FIG. 11 is a genetic map of surface expression vector pBT:pgsA-FMyom expressing fish myostatin mature proteins, according to the present invention.

DETAILED DESCRIPTION OF THE INVENTION, AND

PREFERRED EMBODIMENTS

In one aspect, the present invention relates to a cell surface expression vector containing at least one gene selected from the group consisting of pgsB, pgsC and pgsA genes, which encode a poly-gamma-glutamate synthetase complex, and a polynucleotide encoding a mature domain of myostatin protein, and a recombinant microorganism transformed with the expression vector.

In the present invention, the poly-gamma-glutamate synthetase complex, which is an outer membrane protein encoded by pgsB, pgsC and pgsA genes, has a lot of advantages as a surface anchoring motif expressing foreign proteins on a cell surface due to its primary structure of amino acids and properties thereof. That is, it has advantages in that : first, it can be abundantly exspressed on a cell surface for the synthesis and extracellular secretion of poly-gamma-glutamate; second, the outer membrane protein involved in synthesizing the expressed poly-gamma-glutamate is also maintained stably during the resting stage of cell cycle; third, it is structurally (especially, in case of pgsA) protruded from the cell surface; and fourth, since the outer membrane protein(pgsBCA) is originated from the suface of gram positive bacteria, it can be stably expressed on the surface of gram negative bacteria as well as gram positive bacteria.

In the present invention, as a cell surface expression vector containing genes (pgsB, pgsC and pgsA) encoding said poly-gamma-glutamate synthetase complex, a cell surface expression vector, which is constructed by obtaining pgsBCA from all of Bacillus sp. strains producing poly-gamma-glutamate, may be used, and preferably, a cell surface expression vector containing an outer membrane protein gene involved in synthesizing poly-gamma-glutamate derived from Bacillus subtilis var. chungkookjang (KCTC 0697BP), but it is not limited thereto. For example, the use of an expression vector, which is prepared by using other strain-derived pgsBCA gene having a homology of at least 80% with a base sequence of pgsBCA genes present in Bacillus subtilis var. chungkookjang, will also be within the scope of the present invention.

The myostatin in the present invention is a growth controlling factor, which selectively negative regulates skelectal muscle growth, belongs to TGF-α (transforming growth factor-α) super family and is composed of 375 amino acid precursors, and in the present invention, the mature domain of myostatin protein is a portion obtained by deleting secretion signal and prodomain from the amino acid precursors, which shows myostatin activity.

In the present invention, the myostatin is preferably derived from mammals, birds, or fish. The myostatin has shown a high degree of conservation along evolution in various species and has the same C-terminal fragments of about 109 amino acid residues in mice, rats, human, swine, chickens and turkeys and only 3 amino acid residues in the C-terminal region thereof are not the same in monkeys, cows, and sheep. It is expected that these C-terminal region would include biological active portion of myostatin.

In the present invention, an expression vector and a recombinant microorganism transformed with the expression vector is prepared using myostatin genes of chickens, swine, cows and salmons and, in the case of administering the myostatin expressed by the microorganism to each corresponding animal, it was confirmed that antibodies against myostatin mature protein were produced by inducing immune reaction in the corresponding animal body and thus body weight of each corresponding animal was increased due to the produced antibodies.

The cell surface expression vector of the present invention preferably contains a SlpA7 promoter, and said promoter is a 124-bp promoter, in which a 124bp sequence derived from a HCE promoter and a conserved sequence of 90bp, present in promoters of SIpA gene encoding S-layer protein of lactic acid bacteria, are sequentially linked.

In the present invention, expression efficiency by promoters was examined by inserting SlpA7 promoter and HCE promoter which is a constant high expression promoter, into the same kind of vectors, respectively, and as a result, it was confirmed that the SlpA7 promoter showed a high expression rate compare with the HCE promoter.

Moreover, the surface expression vector is prefarably any one selected from the group consisting of pBT:pgsA-CMyom, pBT:pgsA-PMyom, pBT:pgsA-BMyom and pBT:pgsA-FMyom, and the expression vector contains mature myostatin genes of chickens, swine, cows, and salmons. Any microorganism may be used in the present invention as long as they have no toxicity upon in vivo applications or have been attenuated. Preferably, it is any one selected from the group consisting of E. coli., Salmonella typhi, Salmonella typhimurium, Vibrio cholerae, Mycobacterium bovis, Shigella, Bacillus, lactic acid bacteria, Staphylococcus, Corynebacteria, Listeria monocytogenes and Streptococcus, and the microorganisms is preferably lactic acid bacteria.

In another aspect, the present invention relates to a method for preparing a microorganism having myostatin mature proteins expressed on the surface thereof, the method comprising the steps of expressing the myostatin mature proteins on the surface of the microorganism by culturing the transformed microorganism; and collecting the microorganism having the myostatin mature proteins expressed on the surface thereof.

The inventive myostatin mature protein is expressed in a form fused with poly- gamma-glutamate synthetase protein encoded by pgsB, pgsC and pgsA, which is a gamma-glutamate synthetase complex contained in the expression vector, and the myostatin mature protein is transferred onto the surface of the microorganism by said gamma-glutamate synthetase protein and located thereon.

Since the myostatin mature proteins are expressed on the surface of microorganism without losing its ruction, they can be used with the proteins being expressed on the surface of the microorganism, and thus they can be administered to animals with the proteins being expressed on the surface of the microorganism to induce immune reaction against myostatin in animal body.

In still another aspect, the present invention relates to a feedstuff additive for promoting animal muscle growth and improving animal weight gain, which contains the recombinant microorganism prepared by the method to have the myostatin mature proteins expressed on the surface thereof, as an effective ingredient.

The inventive animal feedstuff additive can be used as preparation for increasing growth rate of breeding animals including cows, swine and chickens.

In still another aspect, the present invention relates to a vaccine for promoting animal muscle growth and improving animal weight gain, which contains the myostatin mature proteins prepared by the method to be expressed on a cell surface, as an effective antibody.

The inventive oral human vaccine may be used as a medical drug for treating and preventing muscle diseases including muscle-wasting diseases and degenerative diseases such as muscular dystrophy and muscular atrophy, or muscle loss caused by AIDS, cancer and the like. In the present invention, the vaccine is preferably administered orally or ingested as food.

In still another aspect, the present invention relates to a method for increasing animal body weight, muscle mass, the number of muscle cells and/or muscle cell size, or decreasing body fat, the method comprises administering the feedstuff additive or the vaccine are administered to animals.

In futher another aspect, the present invention relates to a vaccine for preventing and/or treating muscle-wasting diseases and degenerative diseases, which contains the myostatin mature proteins prepared by the method to be expressed on a cell surface, as an effective antibody.

The inventive vaccine can be administered orally, ingested as food, injected subcutaneously or celiacly, or administered rhinaly to animals including human. When the vaccine containing the myostatin mature proteins prepared by the present invention is administered to vertebrate animals, endogenous mystatin activity in the vertebrate animals is decreased by antibodies produced therefrom, thus showing biological effects such as body weight gain, increased muscle mass, an increase in the number of muscle cells, an increase in muscle cell size, a decrease in body fat, an increase in muscular strength and the like.

Because the number and kind of muscle fiber are determined in embryonic stage, the number of muscle fiber in adult breeding animals will not be increased by the preparation of the present invention. The homology between other members of TGF-α family and myostatin sequences is 30~40% at amino acid level, which is very low, and thus, it will not cause a problem with regard to cross-reactivity of the antibodies against myostatin(GDF-8) in vivo.

Examples

Hereinafter, the present invention will be described in more detail by examples. It is to be understood, however, that these examples are for illustrative purpose only and are not construded to limit the scope of the present invention.

Although the mature form of myostatin was used in the following examples, it may also be used in combination with the protein genes which increase immunity against the myostatin mature protein.

Furthermore, although pgsBCA among outer membrane protein genes involved in the synthesis of poly-gamma-glutamate was obtained from Bacillus subtilis var. chungkookjang (KCTC 0697BP) to use in the following examples, either vectors prepared with pgsBCA gene obtained from all Bacillus sp. producing poly-gamma- glutamate, or microorganisms transformed with these vectors, will also be within the scope of the present invention. For example, either the preparation of vaccine vectors using other strain-derived pgsBCA gene having a homology of at least 80% with the base sequence of pgsBCA gene present in Bacillus subtilis var. chungkookjang, or the use thereof, will also be within the scope of the present invention.

Moreover, although a surface expression vector was prepared only with a pgsA gene among pgsBCA gene in the following examples, as analogized from the indirect examples, the construction of vaccine vectors with all or parts of the pgsBCA genes will also be within the scope of the present invention.

Furthermore, although only Salmonella typhi which is gram-negative bacteria and Lactobacillus which is gram-positive bacteria, were used as hosts for the vectors in the following examples, it will also be obvious to a person skilled in the art that when gram-negative or gram-positive bacteria other than such bacteria, are transformed by the inventive method, the same results can be obtained.

Also in the following examples, only the case, where microorganisms themselves transformed with the vaccine vectors were applied to the living bodies of mice, fowl and pigs, is presented. However, in view of the knowledge in the field of animal feedstuff additives and vaccine-related technologies, it is to be understood that, even when either myostatin mature proteins crudely extracted from said microorganisms or expressed proteins purified from said microorganisms are applied to the living body, the same results can be obtained.

Example 1: Construction of pBT:pgsA-CMyom vector for surface expression

Using a pgsA gene among outer membrane protein genes pgsBCA involved in the synthesis of poly-gamma-glutamate derived from Bacillus sp. strains, a transformation vector pBT:pgsA-CMyom capable of expressing mature domain protein of chicken myostatin on the surface of gram-negative and gram-positive microorganisms as hosts was constructed.

Chicken myostatin sequences are 100% identical to those of swine, mice, human, turkeys and the like. First, pBT:pgsA-amylase(alpha-amylase vector for surface expression: see the Indirect Example 1) was cut with BamRI and Kpnl and then, a surface expression vector pBT:pgsA from which amylase genes were removed, was prepared. In order to introduce a polynucleotide encoding mature domain of myostatin into the vector pBT:pgsA, PCR was performed using a chichen myostatin gene(SEQ ID NO: 1) of 1.3kb which is cloned into PCR T7/NT-TOPO(Invitrogen) as a template, and primers having sequences of SEQ ID NO: 2(5-cgc ggatcc gag gtc aga gtt aca gac aca-3) and SEQ ID NO: 3(5-gga aagctt tta tta tea tga gca ccc gca acg ate a-3). As a result, the CMyom fragment of 369 bp was obtained. The CMyom fragment was cut with restriction enzymes BamHl and Kpnl and linked in accordance with decoding codon to the C-terminal end of the outer membrane protein gene pgsA involved in poly-gamma-glutamate synthesis, of the surface expression vector pBT:pgsA, respectively, thus constructing a vector, pBT:pgsA- CMyom capable of surface-expressing the chicken myostatin mature protein (FIG.

1).

Lactobacillus were transformed with the constructed surface expression vector pBT:pgsA-CMyom and then, the presence of the pBT:pgsA-CMyom plasmid in Lactobacillus was confirmed.

Example 2: Surface expression of pgsA-fused chicken myostatin mature protein

In the present example, it is examined whether the pgsA-fused chicken myostatin mature protein is expressed in Lactobacillus transformed with the surface expression vector pBT:pgsA-CMyom constructed in Example 1. For the expression of the chicken myostatin mature protein, respectively, fused with the C-terminal end of the gene, pgsA involved in the synthesis of poly-gamma- glutamate, a Lactobacillus casei strain transformed with pBT:pgsA-CMyom was stationary cultured in MRS medium {Lactobacillus MRS, Becton Dickinson and Company Sparks, USA) at 37 ^°C , thus inducing the surface expression. The fused protein expression was confirmed by SDS-polyacrylamide gel electrophoresis and Western blotting using a pgsA- and myostatin-specific antibody.

In particular, the whole cell of the expression-induced Lactobacillus casei strain was denatured with a protein obtained at the same cell concentration so as to prepare a sample. The sample was subjected to SDS-polyacrylamide gel electrophoresis, and transferred to PVDF (polyvinylidene-difluoride) membranes (Bio-Rad). The PVDF membranes to which the protein fractions have been transferred were blocked by shaking for 1 hour in a blocking buffer (50 niM Tris HCl, 5% skim milk, pH 8.0), and then, reacted for 12 hours with one thousand fold dilution of rabbit-derived polyclonal anti-pgsA primary antibodies and rabbit- derived polyclonal anti-myostatin primary antibodies in a blocking buffer. After completion of the reaction, the membranes were washed with buffer and reacted for 4 hours with one thousand fold dilution of biotin-conjugated anti-rabbit secondary antibodies in a blocking buffer. After completion of the reaction, the membranes were washed with buffer and reacted with an avidin-biotin reagent for 1 hour, followed by another washing. The washed membranes were color-developed by the addition of a matrix(H₂O₂) and a color development reagent(DAB), thus confirming pgsA-specifϊc antibodies and myostatin-specific antibodies, and the specific binding between the fusion proteins (see FIG. 2).

In FIG. 2, lane 1 represents the whole cell of Lactobacillus casei which was not transformed, and lane 2 represents

casei. As shown in FIG. 2, it could be confirmed that pgsA-CMyom of the specific fusion protein(about 55.5 kDa) was present in the whole cells of each lactic acid bacteria. It could be found that the band of about 55.5 kDa is a fusion protein of pgsA and myostatin mature protein because pgsA has the size of about 42 kDa and the CMyom protein has the size of about 13.5 kDa.

Moreover, in order to confirm whether the fusion protein was expressed on the surface of lactic acid bacteria by anti-pgsA antibodies and anti-myostatin antibodies in lactic acid bacteria transformed with the pBT:pgsA-CMyom surface expression vector or not, the lactic acid bacteria transformed with each vector were divided into a cell wall fraction and a cytoplasm fraction by means of cell fractionation using a ultaracentrifuge, and then the location of each fusion protein was confirmed by Western blot analysis using pgsA-specific antibodies and myostatin-specific antibodies.

Particulary, Lactobacillus, on the surface of which fusion protein are expressed using the method described above, was collected so as to be the same cell concentration as that of non-transformed Lactobacillus, and the cells were washed several times with TES buffer solution(10 rnM Tris-HCl, ρH8.0, 1 mM EDTA, 25% sucrose), then suspended with a distilled water containing 5 mg/mϋ lysozyme, 1 mM PMSF and 1 mM EDTA, followed by repeating freezing at -60 ^°C and thawing to room temperature several times to disrupt the cells using ultrasonic waves after adding DNase (0.5 mg/m.0) and RNase (0.5 mg/mu) thereto. Next, the non-disrupted whole cells of Lactobacillus (pellet: whole cell fraction) and the celluar debris were seperated by centrifuging the disrupted cell suspension at 4 ^°C for 20 minutes under 10,000 g, and then, the separated cellular debris was centrifuged at 4^°C for 1 hour under 21,000 g, thus obtaining cellular debris(soluble fraction) containing the Lactobacillus cytoplasmic protein and the pellet. This obtained pellet was suspended in TE solution (10 mM Tris-HCl, ρH8.0, 1 mM EDTA, pH 7.4) to obtain the cell wall protein (cell wall farction) of Lactobacillus.

It could be confirmed that the myostatin mature protein fused with pgsA among each of the Lactobacillus fraction was located on the cell wall, by SDS- polyacrylamide gel electrophoresis and Western blotting using pgsA-specifϊc antibodies and myostatin-specific antibodies (FIG. 2). In FIG.2, lane 3 and lane 4 represent the soluble faction and the cell wall fraction of the strain transformed with pBT:pgsA-CMyom, respectively. As shown in FIG.2, the myostatin mature protein fused with pgsA of about 55.5 kDa was confirmed in the whole cell of lactic acid bacteria and cell wall fraction. Fron these results, it could be seen that the myostatin mature protein fused with pgsA was expressed and then moved to the suface of lactic acid bacteria, thus being located thereon.

Example 3: Immune response induction by Lactobacillus expressing myostatin mature proteins on their surface in mice and body weight change thereby

Lactobacillus casei, which are gram-positive bacteria, were transformed with the surface expression vector pBT:pgsA-CMyom, and then, the antigens were expressed on the surface of Lactobacillus casei using the same method described in Example 2, then examining immune tolerance inducement of myostatin mature protein fused with the outer membrane protein pgsA involed in poly-gamma- glutamate synthesis and body weight changes thereby using a mouse model.

Specifically, the surface expression vector pBT:pgsA-CMyom according to the present invention was transformed into Lactobacillus casei and then cultured to collect cells. The collected cells were washed with PBS buffer (pH7.4), and the Lactobacillus (5 x 10⁹ cells) having the antigen expressed on their surface were orally administered to 4-6-week old B6SJL mice. At this time, each experimental group consisted of ten mice, and they were orally administered to the group five times at an interval of one-day, and after one week, five times at an interval of one- day, and after one week, five times at an interval of one-day and after 2 weeks, five times at an interval of one-day. And the broth, in which only the lactic acid bacteria were cultured, was administered to a control group, the B6SJL mice with the same schedule.

At about 5, 9, 13, 17 and 21 weeks after the initial oral administration, the mouse sera were collected and and measured for IgG antibody titer against the myostatin mature protein in serum by ELISA.

FIG 3. shows the IgG antibody titer against the myostatin antigen protein, A is the group administered with the lactic acid bacteria expressing the myostatin mature protein on its surface, and B is the group administerd only with lactic acid bacteria. As shown in FIG.3, it could be confirmed that, in the serum of the B6SJL mice to which the Lactobacillus casei transformed with pBT:pgsA-CMyom have been administered, IgG antibody titers against mature myostatin antigen proteins were significantly higher than that in the control group. Therefore, it was confirmed that microorganisms having myostatin mature proteins of the present invention expressed on the surface thereof can effectively produce antibodies against myostatin mature proteins.

Additionally, at an interval of a week after the oral administration, the weight of B6SJL mouse was measured to compare and analyze the differnces between the groups. FIG. 4 graphically shows the weight differences between the experimental group (A) to which the lactic acid bacteria expressing the myostatin mature proteins on their surface were administered and the control group (B) to which the general lactic acid bacteria were administered, and from about 6 weeks after the administration of Lactobacillus casei transformed with pBT:pgs A-CMy om, the weight of the B6SJL experimental group were significantly high, and it was found that it showed significant differences as time goes on. The above weight-gain phenomenon is caused by the operation of antibodies against the myostatin mature proteins produced and induced by the inventive microorganisms expressing the myostatin mature protein on their surface. Example 4: Immune response induction by Lactobacillus expressing myostatin mature proteins on their surface in chicks and body weight change thereby

Lactobacillus casei were transformed with pBT:pgsA-CMyom using the same method described in Example 2 to preprare Lactobacillus casei expressing the myostatin mature proteins on their surface by the the outer membrane protein pgsA, and then, immune tolerance inducement of myostatin mature proteins and the weight change thereby, were examined in chicks using the surface-expressing Lactobacillus casei.

Specifically, the surface expression vector pBT:pgsA-CMyom according to the present invention was transformed into Lactobacillus casei and an experiment was carried out by using assorted feed for Cobb breed chicks, which is mixed with the Lactobacillus expressing the myostatin mature proteins on their surface. Experiments were conducted on 4 groups of experimental groups A, B and corresponding control groups, each group consisting of 30 chicks.

In the experimental groups, the chicks in the control group was fed with the assorted feed only, and the experimental group A was fed with the assorted feed mixed with 0.5% culture broth of Lactobacillus having the myostatin mature proteins expressed on the surface thereof during the first 1 week, then fed with the assorted feed only at 2, 3, 4 and 5 weeks. The experimental group B was fed with the assorted feed mixed with 0.5% culture broth of Lactobacillus having the myostatin mature proteins expressed on the surface thereof during the first 1 week, and fed with the assorted feed mixed with 0.1% culture broth of Lactobacillus having the myostatin mature proteins expressed on the surface at 2 and 3 weeks, then fed with the assorted feed only at 4 and 5 weeks. The experimental group C was fed with the assorted feed mixed with 0.5% culture broth of Lactobacillus having the myostatin mature proteins expressed on the surface thereof during the first 1 week, and fed with the assorted feed mixed with 0.1% culture broth Lactobacillus having the myostatin mature proteins expressed on the surface at 2, 3, 4 and 5 weeks. At about 5 weeks after the begining of the experiment, the chicken sera were collected and measured for IgG antibody titer against the myostatin mature protein in serum by ELISA.

FIG 5. shows the average IgG antibody titer against the myostatin antigen protein in the sera of the chicks in the experimental group, it could be confirmed that the antibody titer of the experimental group, fed with the assorted feed mixed with the culture broth of lactic acid bacteria having the myostatin mature proteins expressed on the surface thereof, was higher than that of the control group fed with only the assorted feed, and, the experimental group continuously fed with the culture broth of lactic acid bacteria during 3 or 5 weeks, showed relatively high IgG antibody titer. Thus, it could be seen that the antibodies against the myostatin mature proteins were effectively produced in chicks by the lactic acid bacteria having myostatin mature proteins expressed on the surface thereof.

Additionally, at an interval of a week, in each experimental group fed with culture broth of Lactobacillus having the myostatin mature proteins expressed on the surface thereof, the weight of chicks was measured to compare and analyze weight differnces among the groups. As shown in FIG. 6, in the graph showing weight differences among the control group(D), the experimental group(A), the experimental group(B), and the experimental group(C), the weight differences among experimental groups began to show at the second week and, at 5th week, the average weght of the control group was 1507.68 g, and the the average weight of each group is as follows: that of the experimental group A was 1697.48 g, that of the experimental group B was 1747.93 g, and that of the experimental group C was 1797.20 g. Like the experimental group of mice, it could be confirmed that the experimental group fed with the culture broth of the lactic acid bacteria having the myostatin mature proteins expressed on the surface thereof for a long period of time, showed significantly increased body weight compared with the contol group. These weight-gain phenomenon was caused by the activity of antibodies against myostatin mature proteins, produced by lactic acid bacteria having myostatin mature proteins expressed on the surface thereof, according to the present invention.

In addition, the feedstuff additive efficiency of each experimental group(the total amount administerd/total weight of the chicks) was measured (FIG. 7). As a result, as shown in FIG. 7, the experimental group C showed the highest level of feedstuff efficiency.

Example 5: Immune response induction by Lactobacillus surface-expressing myostatin mature proteins in pigs and body weight change thereby

Vector pKT:pgsA-PMyom capable of expressing porcine myostatin mature protein on its surface was prepared by the same method as described in Example 1, and Lactobacillus casei were transformed with the surface expression vector pKT:pgsA- PMyom which expresses the porcine myostatin mature protein on its surface by the same method as described in Example 2, thus examining immune tolerance inducement of porcine myostatin mature protein and weight changes thereof using Lactobacillus casei which express the transformed myostatin mature protein on their surface.

For the expression of the porcine myostatin mature protein fused with the C- terminal end of the gene pgsA involved in the synthesis of poly-gamma-glutamate, a Lactobacillus casei strain transformed with pkT:pgsA-PMyom were stationary cultured in MRS medium {Lactobacillus MRS, Becton Dickinson and Company Sparks, USA) at 30^°C for 16 hours, thus inducing the surface expression. The expression of the fusion proteins was confirmed by SDS-polyacrylamide gel electrophoresis and Western blotting using pgsA-specific antibodies and myostatin- specifϊc antibodies (FIG. 8). In FIG. 8, lane 1 is non-transformed Lactobacillus casei, and lane 2~4 are pKTipgsA-YMyom/Lactobacillus casei. As shown in FIG. 8, pgsA-PMyom of the specific fusion protein (about 56.5 kDa) in each of the lactic acid bacteria cell was confirmed, suggesting that the band showing 56.5 kDa as the above was the fusion protein having pgsA fused with the myostatin mature protein, since pgsA linker was about 43 kDa, and PMy om was about 13.5 kDa.

Specifically, an animal experiment was carried out as follows; Lactobacillus casei were transformed with pKT:pgsA-PMyom, and the broth solution of Lactobacillus having the myostatin mature proteins expressed on the surface thereof was concentrated ten times, to orally administer to young pigs directly. The experimental pigs were divided into group A and group B and corresponding control groups, and the experimental pigs for each group were 15.

In the myostatin experimental group (A myo group, B myo group), Lactobacillus casei were transformed with pKT:pgsA-PMyom, and the broth solution of Lactobacillus having the myostatin mature proteins expressed on the surface thereof was concentrated ten times, and then 10ml of the concentrate was orally administered to young pigs everyday for 10 days, and in the control group (A con group, B con group), the young pigs were bred with a conventional breeding method, with no administration. The myostatin experimental group A (A myo group) was administered with the Lactobacillus concentrate having the myostatin mature proteins expressed on the surface thereof for 10 days after weaning, bred for 132 days, and the experiment was terminated, and the myostatin experimental group B (B myo group) was administerd with the concentrate, beginning on day 20 (6 days before weaning) for 10 days, then bred for 126 days, and the experiment was terminated. After the experiment was terminated, the weight difference among the experimental groups to which the culture broth of lactic aicd bacteria having the myostatin mature proteins expressed on the surface thereof was administred, and the control groups, was compared and analyzed. As shown in FIG.9, the graphs show the weight changes between the begining and the end of the experiment in each of the group (FIG. 9).

As shown in FIG. 9, like the experiments using mice and chicks, it was confirmed that the experimental group fed with the culture broth of the lactic acid bacteria having the myostatin mature proteins expressed on the surface thereof, showed significantly increased body wieght compared with the contol group. The weight was measured for individual pigs before and after the experiment. The experimental results show that, before the experiment, the weights were similar in the control groups and the myo group A and the myo group B, but, after the experiment, in the group A, the myostatin experimental group showed about 10.5% of weight gain compared to the control group, and, in the group B, it was found that pig weight of myostatin experimental group was increased by about 11.5% compared to the control group. These weight-gain phenomenon was caused by the activity of antibodies against myostatin mature proteins, produced by lactic acid bacteria having myostatin mature proteins expressed on the surface thereof, according to the present invention.

In addition, the weight of the myostatin experimental group B, to which the concentrate of lactic acid bacteria had been administered beginning on day 20, was significantly increased compared with the myostatin experimental group A, to which the concentrate of lactic acid bacteria had been administered beginning on day 28, thus suggesting that administration of the lactic acid bacteria having the myostatin mature proteins expressed on the surface thereof to young pigs is more effective.

Example 6: Construction of surface expression vector pBT:pgsA-BMyom

Using a pgsA gene among outer membrane protein genes pgsBCA involved in the synthesis of poly-gamma-glutamate derived from Bacillus sp. strains, transformation vector pBT:pgsA-BMyom capable of expressing the mature domain of bovine myostatin on the surface of gram-negative and gram-positive microorganisms as hosts was constructed.

The bovine myostatin sequences are 100% identical to those of monkeys, sheep, etc., but is different from pigs, chickens, mice etc, including humans in 3 amino acids. First, in order to introduce bovine myostatin genes after removing CMyom gene from the surface expression vector (pBT:pgsA-CMyom), PCR was performed using a bovine myostatin gene(SEQ ID NO: 4) of 1.3 kb which is coined in PCR T7/NT-TOPO as a template, and primers having sequences of SEQ ID NO: 5 (5-cgc ggatcc gag gtc aga gtt aca gac a-3) and SEQ ID NO: 6 (5-gga aagctt tta tta tea tga gca ccc gca acg atc-3), which are derived from a gene encoding the mature domain(BMyom). As a result, the BMyom fragment of 369 bp was obtained. The BMyom was cut with restriction enzymes BamHl and Kpnl to link in accordance with decoding codon to the C-terminal end of the outer membrane protein gene pgsA involved in poly-gamma-glutamate synthesis of the surface expression vector pBT:pgsA, respectively, thus constructing a transformation vector, pBT:pgsA- BMyom (FIG. 10).

Lactobacillus, which were gram-positive bacteria, were transformed with the constructed surface expression vector pBT:pgsA-BMyom, and then, the presence of the pBT:pgsA-BMyom plasmid in Lactobacillus was confirmed.

Example 7: Construction of surface expression vector pBT:pgsA-FMyom

Using a pgsA gene among outer membrane protein genes pgsBCA involved in the synthesis of poly-gamma-glutamate derived from Bacillus sp. strains, transformation vector pBT:pgsA-FMyom capable of expressing the mature domain of fish(salmon) myostatin on the surface of gram-negative and gram-positive microorganisms as hosts was constructed. Myostatin sequences of fish(salmon) have less than 70% sequence similarity to other vertebrate animals. First, in order to introduce fish(salmon) myostatin genes after removing CMyom gene from the surface expression vector (pBT:pgsA- CMyom), PCR was performed using a fish(salmon) myostatin gene(SEQ ID NO: 7) of 1.1kb which is coined in a pGEM-T vector (Promega Co.) as a template, and primers having sequences of SEQ ID NO: 8 (5-cgggatcc GAT TCG GGC CTG GAC TGT GAT GAG-3) and SEQ ID NO: 9 (5-ggggtacc TCA CGA GCA GCC GCA GCG GTC C-3), which are derived from a gene encoding the mature domain(FMyom). As a result, the FMyom fragment of 369 bp was obtained. The gene fragment was cut with restriction enzymes BamHl and Kpnl to link in accordance with decoding codon to the C-terminal end of the outer membrane protein gene pgsA involved in poly-gamma-glutamate synthesis of the surface expression vector pBT:pgsA, respectively, thus constructing a transformation vector, pBT:ρgsA-FMyom (FIG. 11).

Lactobacillus, which were gram-positive bacteria, were transformed with the constructed surface expression vector pBT:pgsA-FMyom, and then, the presence of the pBT:pgsA-FMyom plasmid in Lactobacillus was confirmed.

Indirect Example 1: Construction of surface expression vector pBT-pgsA

In order to increase the surface expression rate of the surface expression vector pHCE2LB:pgsA including a constant high expression promoter, HCE promoter in pAT which is gram-positive and gram-negative general purpose vector and a pgsA gene among the outer membrane protein genes(pgsBCA) involved in poly-gamma- glutamate synthesis, on gram-positive and gram-negative microorganisms as hosts using a pgsA gene among outer membrane protein genes pgsBCA involved in the synthesis of poly-gamma-glutamate derived from Bacillus sp., a study was performed to screen a modified promoter with high expression rate, and HCE promoter region of pHCE2LB:pgsA vector was replaced with the modified promoter, thus constructing a vector, pBT-pgsA.

Specifically, in the pBT-pgsA including SlpA7 promoter which is a constant high expression promoter in gram-negative and gram-positive general purpose vector pAT and a pgsA gene among the outer membrane protein genes pgsBCA involved in poly-gamma-glutamate synthesis, HCE promoter in pHCE2LB:pgsA-HPVLl (KCTC 10349BP) was replaced with SlρA7 promoter.

In order to compare the expression rates between the HCE promoter and the SlpA7 promoter, each of the promoters were inserted into a secretion expression vector of alpha-amylase(a vector having alpha-amlylase inserted into the pHCE2LB plasmid together with secretion signal of alpha-amlylase, from which pgsA was deleted), and the expression rates of promoters were comfirmed indirectly by measuring the enzymatic activity of secreted alpha-amylase.

The HCE promoter (229 bp) and SlpA7 promoter (214 bp) were inserted into a E. coli-Lactobacillus shuttle vector, pAT vector, respectively using restriction enzyme sites, Spel and BgIII and two kinds of plasmids (pAT-HCE-AmylSS-amylase, pAT- SlpA7-AmylSS-amylase), in which secretion signal peptide of alpha-amylase and alpha-amylase gene were sequentially linked, were constructed such that amylase can be secreted and expressed by the promoters.

The SlpA7 promoter has 214 bp base sequence (SEQ ID NO: 10), in which 90 bp portion selected, based on consensus sequence in the promoters of SIpA gene encoding S-layer protein in lactic acid bacteria is sequentially linked to the 124 bp derived from the HCE promoter, and has restriction sites, Spel and Bglϊl on both terminal ends.

The lactic acid bacteήa(Lactobacillus cαsei) transformed with each of the constrcted plasmids were cultured in an MRS solid medium supplemented with 1% starch for a given time to confirm the secretion of alpha-amylase by measuring the dissolved degree of the starch contained in the medium by the secreted alpha- amylase using iodine dyeing, and after the bacteria were liquid cultured in MRS medium added with antibiotics, erythromycin to the final consentration of 16 μg I mi for plasmid maintenance, for a given time, the activity of alpha-amylase secreted into the medium was measured. In order to measure the activity of alpha-amylase in culture supernatant, activity assay kit (Kikkoman Co., Tokyo, Japan) was used. N3- G5-j8-CNP(2-chloro-4-nitrophenyl 6⁵-azido-6⁵-deoxy-j3-maltopentaoside) was used as a substrate, and a solution containing 100 μJL culture supernatant and 400 μi substrate was allowed to react at 37^°C for 10 minutes to terminate the reaction by adding 800 μJi reaction stopping solution, thus measuring the absorbancy at 400nm. 1 unit activity was defϊnd as the amount of enzyme required for producing 1 μmole of CNP(2-chloro-4-nitrophenol), from N3-G5-/5-CNP by the absorbance at 400nm at 37 ^°C for 1 minute. As shown in the results of the activity measurement, the alpha-amylase activity by the SlpA7 promoter was 0.234 λxmXlμA and the alpha- amylase activity by the HCE promoter was 0.052 λxrάXlμi (Table 1), suggesting that the alpha-amylase activity by SlpA7 promoter is about 4.5-fold higher than that by HCE promoter. Therefore, it was confirmd that the expression rate of the SlpA7 promoter was 4.5-fold higher than that of the HCE promoter

Table 1

INDUSTRIAL APPLICABILITY As described above, the present invention has an effect to provide a cell surface expression vector containing a gene encoding a poly-gamma-glutamate synthetase complex and a polynucleotide encoding a mature domain of myostatin protein, and a microorganism transformed with the vector. Moreover, the present invention has an effect to provide a method for preparing a microorganism observed in the knockout mice, and a feedstuff additive or a vaccine containing myostatin mature proteins, which is prepared by the method to be expressed on a cell surface, as an effective ingredient. The inventive feedstuff additive or vaccine containing the myostatin mature proteins expressed on a cell surface, as an effective ingredient, can be used for preventing and treating muscle- wasting diseases and degenerative diseases such as muscular dystrophy, muscular atrophy and the like, as well as increasing and controlling muscle growth of livingstock and poultry. In addition, the transformed strain observed in the knockout mice shows the same effect even if the strain itself after culturing is directly used, and thus it is very economical.

While the present invention has been described with reference to the particular illustrative embodiment, it is not to be restricted by the embodiment but only by the appended claims. It is to be appreciated that those skilled in the art can change or modify the embodiment without departing from the scope and spirit of the present invention.

Claims

THE CLAIMS What is claimed is:

1. A cell surface expression vector containing at least one gene selected from the group consisting of pgsB, pgsC and pgsA genes, which encode a poly-gamma- glutamate synthetase complex, and a polynucleotide encoding a mature domain of myostatin protein.

2. The expression vector according to claim 1, wherein the myostatin is derived from mammals, birds(poultry) or fish.

3. The expression vector according to claim 1, which contains SlpA7 promoter.

4. The expression vector according to claim 1, which is any one selected from the group consisting of pBT:pgsA-CMyom, pBT:pgsA-PMyom, pBT:pgsA-BMyom and pBT:pgsA-FMyom, .

5. A recombinant microorganism transformed with the expression vector of any one claim among claims 1 to 4.

6. The recombinant microorganism according to claim 5, wherein the microorganism is any one selected from the group consisting of E. coli., Salmonella typhi, Salmonella typhimurium, Vibrio cholerae, Mycobacterium bovis, Shigella, Bacillus, lactic acid bacteria, Staphylococcus, Corynebacteria, Listeria monocytogenes and Streptococcus.

7. The recombinant microorganism according to claim 5, wherein the microorganism is lactic acid bacteria.

8. A method for preparing a microorganism having myostatin mature proteins expressed on the surface thereof, the method comprising the steps of; (a) expressing myostatin mature proteins on the surface of the microorganism by culturing the recombinant microorganism of claim 5; and collecting the microorganism having the myostatin mature proteins expressed on the surface thereof.

9. A feedstuff additive for promoting animal muscle growth and improving animal weight gain, which contains the microorganism obtained by the method of claim 8 to have myostatin mature proteins expressed on the surface thereof, as an effective ingredient.

10. A vaccine for promoting animal muscle growth of animals and improving animal weight gain, which contains the myostatin mature proteins prepared by the method of claim 8 to be expressed on the cell surface, as an effective antibody.

11. The vaccine according to claim 10, which can be administered orally or ingested as food.

12. A method for increasing animal body weights, muscularities, the number of muscle cells and/or muscle cell sizes, or decreasing body fat, the method comprises administering the feedstuff additive of claim 9 or the vaccine of claim 10 to animals.

13. A vaccine for preventing and/or treatmenting a muscle-wasting diseases and degenerative diseases, which contains the myostatin mature protein prepared by the method of claim 8 to be expressed on the cell surface, as an effective antibody.

14. The vaccine according to claim 13, which can be administered orally or ingested as food.