NZ289197A - Alpha lactalbumin gene constructs and transgenic cattle - Google Patents

Description

New Zealand No. 289197 International No. PCT/GB95/01651 TO BE ENTERED AFTER ACCEPTANCE AND PUBLICATION Priority dates: 13.07.1994; 15.12.1994;31.01.19u95;25.02.19 95; Complete Specification Filed: 12.07.1995 Classification:^) C12N15/12; A01K67/027; A23C9/00 Publication date: 24 September 1998 Journal No.: 1432 NEW ZEALAND PATENTS ACT 1953 COMPLETE SPECIFICATION Title of Invention: Alpha-lactalbumin gene constructs Name, address and nationality of applicant(s) as in international application form: PPL THERAPEUTICS (SCOTLAND) LIMITED, Roslin, Edinburgh EH25 9PP, Great Britain Q 0 b: t ij i WO 96/02640 PCT/GB9S/01651 1 "Alpha-Lactalbumin Gene Constructs" 2 3 The present invention is concerned with recombinant 4 gene constructs for expressing the protein a- lactalbumin, or functional equivalents or parts 6 thereof. 7 8 Human milk has been shown to be superior over other 9 milk types, notably cow, sheep, camel and goat milk, for human infant nutrition. However, many mothers find 11 breast feeding difficult or inconvenient. Moreover, in 12 countries where infant food supplements are in great 13 demand, it would be highly desirable to be able to 14 supply a milk product with the nutritional benefits of human milk. 16 17 One of the major differences of human milk over milk 18 from other mammals (for example cows or sheep) is the 19 presence of a-lactalbumin as the major whey protein. 2 0 Whilst a-lactalbumin is present in other milk types, 21 the concentration is relatively low and instead the 22 major whey protein is /3-lactoglobulin. The level of a- 23 lactalbumin varies from species to species, with human 24 milk containing about 2.5 mg/ml, cow milk 0.5-1.0 mg/ml and mouse milk 0.1-0.8 mg/ml.

SUBSTITUTE SHEET (RULE 26) ACTIVE AS AT ACCEPTANCE . WO 96/02640 PCT/GB95/01651 2 f;. *7 1 The gene sequences encoding for the bovine-'a- 2 lactalbumin and for the human a-lactalbumin proteins 3 have been elucidated and the sequence information 4 published by Vilotte et al, in Biochemie jjj).: 609-620 (1987) and by Hall et al, in Biochem J 242; 735-742 6 (1987), respectively. 7 8 The present invention seeks to utilise genetic 9 engineering techniques to provide a recombinent gene construct capable of producing an a-lactalbumin 11 concentration of greater than 1.0 mg/ml, for example 12 1.2 mg/ml or above, in milk when expressed in mammalian 13 cells. Generally said construct is adapted to be 14 expressed in non-human animal, especially bovine, cells, 16 17 In general terms, the present invention, provides.a 18 recombinant expression system adapted to express a- 19 lactalbumin, or a functional equivalent or part thereof in cells of a non-human, preferably bovine, animal. 21 Preferably, the recombinant expression system of the * 22 present invention is adapted to express the human a- 23 lactalbumin protein, or a functional equivalent or part 24 thereof. 26 The term "expression system" is used herein to refer to 27 a gerretic sequence which includes a protein-encoding 2 8 region and is operably linked to all of the genetic 29 signals necessary to achieve expression of the protein encoding region. Optionally, the expression system may 31 also include a regulatory element, such as a promoter 32 or enhancer, to increase transcription and/or 33 translation of the protein-encoding region, or to 34 provide control over expression. The regulatory element may be located upstream or downstream of the 36 protein-encoding region, or may be located at an intron ACTIVE AS AT ACCEPTANCE WO 96/02640 PCT/GB95/01651 • 1 (non-coding portion) interrupting the protein encoding 2 region. Alternatively it is also possible for the 3 sequence of the protein-encoding region itself to 4 comprise a regulatory ability. 6 The term "functional equivalent" refers to any 7 derivative which is functionally substantially similar 8 to the reference sequence or protein. In particular 9 the term "functional equivalent" includes derivatives in which nucleotide base(s) and/or amino acid(s) have 11 been added, deleted or replaced without a significantly 12 adverse effect on biological function, especially 13 biological function in milk production. 14 Genetic engineering has been recognised as a powerful 16 technique not only in research but also for commercial 17 purposes. Thus, by using genetic engineering 18 techniques (see Maniatis et al Molecular Cloning, a 19 Laboratory Manual Cold Spring, Harbor Laboratory, Cold Spring Harbor, New York 1982 and "Principle of Genetic 21 Engineering", Old and Primrose, 5th edition, 1994 f both 22 incorporated herein by reference) exogenous genetic 2 3 material can be transferred to a host cell and the 24 protein or polypeptide encoded by the exogenous genetic material may be replicated by and/or expressed within 26 the host. For the purposes of simplicity genetic 27 engineering is normally carried out with prokaryotic 2 8 micro-organisms, for example bacteria such as E. coli. 2 9 as host. However, use has also been made of eukaryotic organisms, in particular yeasts or algae, and in 31 certain applications eukaryotic cell cultures may also 32 be used. 33 34 Genetic alterations to mammalian species by micro- injection of genes into the pro-nuclei of single-cell 35 embryos has been described by Brinster et al, in Cell WO 96/02640 PCT/GB95/01651 u 1 2_7 : 223-231, 1981. Here the foreign genetic material 2 is introduced into the fertilised egg of an animal 3 which then proceeds to develop into an embryo in the 4 normal manner having been transplanted into a foster mother. Truly transgenic animals contain copies of the 6 exogenous DNA in each cell. 7 8 Where the injected genetic material is successfully 9 incorporated into the host chromosome the animal is termed "transgenic" and the transgene is inherited in 11 the normal Mendelian manner. However, only a low 12 proportion of gene transfer operations are successful, 13 especially for large domestic animals such as pigs, 14 sheep and cattle. To date it has not been possible to control the location at which the transgene integrates 16 into the host chromosome for such animals. 17 18 For the purpose of the present invention it may, in 19 certain circumstances, be sufficient simply to produce a "mosaic" donor animal. In this situation the* 21 transgene is incorporated into the chromosome copies of 22 only certain body organs. Mosaic animals are generally 23 produced by introducing exogenous DNA into an embryo at 24 a later developmental stage. 26 One of the most promising application of transgenesis 27 in lfvestock aims to utilise the mammary gland as a 28 "bioreactor" to produce recombinant proteins of 29 pharmaceutical or nutritional interest in milk. The mammary gland is an attractive organ in which to 31 express heterologous proteins due to its capacity to 32 produce large quantities of protein in an exocrine 33 manner. Recombinant DNA techniques may be used to 34 alter the protein composition of cow's milk used for human or animal consumption. For example, the 36 expression of human milk proteins in cow's milk could .WO 96/02640 PCT/GB95/01651 " 5 1 improve its nutritional value in infant formula 2 applications (Strijker et al, in Harnessing 3 Biotechnology for the 21st Century, ed Ladisch and 4 Boser, American Chemical Society, Pages 38-21 (1992)).

Both applications would benefit from ability to 6 increase production capacity inexpensively by 7 multiplying producer animals with conventional and 8 advanced breeding techniques. 9 The first step in developing a transgene to be 11 expressed in the mammary gland is to clone the gene for 12 the protein of interest. To direct expression into 13 milk, the promoter gene for a major milk protein 14 expressed in milk is employed. Milk protein genes are tightly regulated and are not expressed in tissues 16 other than the mammary gland, a characteristic that 17 minimises the possibility of negative effects on the 18 animal from inappropriate expression in other tissues. 19 Among the regulatory genes used to express heterologous proteins in the mammary gland are alpha-Sj-casein 21 (Strijker et., 1992, supra), beta-lactoglobulin (Wright 22 et al., Bio/Technology 5.: 831-834 ( 1991)) whey acidic 23 protein (Ebert and Schindler, Transgenic Farm animals: 24 Progress Report (1993)) and beta-casein (Ebert and Schindler, 1993, supra). 26 27 Newly-made gene constructs are normally tested in 28 transgenic mice before adopting them for use in cattle. 29 Milk obtained from the transgenic mice is assayed for quantity of recombinant protein. If enough milk is 31 available, the protein may be isolated to examine its 32 structural characteristics and bioactivity. The 33 selection of a particular construct for use in cattle 34 will depend primarily on consideration of both expression level and authenticity of the resultant 36 recombinant protein. 6 PCT/GB9S/01651 1 Transgenesis in cattle is normally initiated by 2 microinjecting several hundred copies of gene construct 3 into one of the two pronuclei in a zygote. Zygotes may 4 be obtained in vivo from the oviducts (Roschlau et al., Arch Tierz. Berlin JU:3-8 (1988); Roschlau et al., in 6 J. Reprod. Fertil. (suppl 38), Cell Biology of 7 Mammalian Egg Manipulation, ed Greve et al (1989); Hill 8 et al. , Theriogenology 37.: 222 (1992); Bowen et al. Biol 9 Reprod. j>0:664-448 (1994)) or by in vitro fertilisation of in vitro matured oocytes (Krimpenforth et al., 11 Biotechnology 9.:844-847 (1991); Hill et al., 1992, 12 supra; Bowen et al., 1993 supra). Bovine zygotes must 13 be centrifuged at 15,000 x g for several minutes to 3 4 displace opaque lipid in order to visualise the pronuclei with phase contrast, Nomarski or Hoffman 16 interference contrast optics. 2-4 pi of buffer 17 containing several hundred copies of DNA construct are 18 injected into a pronucleus. Transgenes are thought to 19 integrate into random breaks in chromosomal DNA that result from mechanical disruption during the 21 microinjection process. Ideally, the transgenes 22 integrate at the zygote stage prior to DNA replication 23 to ensure that every cell in the adult contains the 24 transgene. In general, several "copies" of the transgene, linked together linearly, integrate in a 26 single site on a single chromosome. The site of 27 integration is random. Integration probably occurs 28 after the first round of DNA replication, and perhaps 29 as late as the 2- or 4- cell stage (Wall and Seidel, 1992), resulting in animals that are mosaic with 31 respect to the transgene. Indeed, up to 30% of animals 32 in which transgenes are detected in somatic tissues do 33 not transmit the transgenes to their offspring (or 34 transmit to less than the expected 50%). 36 After microinjection, embryos are either transferred 7 1 directly into the oviducts of recipients or cultured 2 for a few days and transferred to the uterus of 3 recipient cattle. Confirmation of transgene 4 integration is obtained by Southern blot analysis of tissues sampled from the calf after birth. Transgene 6 expression is measured by assaying for the gene product 7 in appropriate tissues, or in this case milk. Embryo 8 survival after microinjection, transgene integration 9 frequency, frequency of expression and expression level, and frequency of germline transmission vary 11 according to quantity and quality of DNA construct 12 injected, strain of mice used (Brinster et al., Proc. 13 Natl. Acad Sci. USA 82.:4438-4442 (1985)) and skill and 14 technique of the operator performing microinjection.

This basic approach has been routinely applied to 16 produce transgenic sheep (Wright et al., 1991, supra), 17 goats (Ebert and Schindler, 1993, supra) pigs (Rexroad 18 and Purcel, Proc 11th Intl. Congr. Anim. Reprod. A.I. 19 Dublin j>:29-35 (1988)) and cattle (Krimpenfort et al., 1991, supra; Hill et al., 1992, supra; Bowen et al., 21 1994, supra). 22 23 Reference is also made to WO-A-88/01648 (of Immunex 24 Corporation), to WO-A-88/00239 and to WO-A-90/05188 (both of Pharmaceutical Proteins Limited) for 26 describing suitable techniques and methodologies for 27 production of recombinant gene constructs, production 28 of transgenic animals incorporating such constructs and 29 expression of the protein encoded in the mammary gland of the lactating adult female mammal. The disclosures 31 of these references and the references recited above 32 are incorporated herein by reference. 33 34 Reference is further made to Stacey et al in molecular and Cellular Biology 14(2); 1009-1016 (February 1994) 36 which describes a knock-out experiment in which the WO 96/02640 fTCT/GB?5/01651 Q £:. ( '• • ' : / S 1 ^^ v tV .v 1 mouse a-lactalbumin gene is replaced with a human a- 2 lactalbumin gene. This paper (incorporated herein by 3 reference) does not however report expression of the a- 4 lactalbumin protein. 6 In one embodiment the present invention provides an 7 expression system which has been produced by techniques 8 other than by knock-out of the gene naturally present. 9 In general"-terms, the present invention also provides a- 11 transgenic mammalian animal, said animal having cells 12 incorporating a recombinant expression system adapted 13 to express a-lactalbumin (preferably human a- 14 lactalbumin) or a functional equivalent or part thereof. Generally the recombinant expression system 16 will be integrated into the genome of the transgenic 17 animal and will thus be heritable so that the offspring 18 of such a transgenic animal may themselves contain the 19 transgene and thus also be covered by the present invention. Suitable transgenic animals include (but 21 are not limited to) sheep, pigs, cattle and goats. 22 Cattle are especially preferred. 23 24 Additionally, in general terms the present invention comprises.a vector containing such a recombinant expression system and 26 host cells transformed with such a recombinant 27 expression system (optionally in the form of a vector). 28 Accordingly, in one aspect the present invention provides a recombinant DNA construct comprising, in the 5' to 3' direction and operatively linked: (a) the 5' flanking sequence of SEQ ID NO 21; (b) a DNA sequence encoding (1) a signal sequence and (2) a-lactalbumin or a functional equivalent thereof; and (c) the 3' flanking sequence of anyone of SEQ ID NO'S 16 to 20; the DNA construct being adapted to express the a-lactalbumin or fi&ictionai equivalent thereof in a non-human transgenic animal.

In another aspect, the present invention provides a recombinant DNA construct comprising, in the 5' to 3' direction and operatively linked: (a) at least about 1.8 kb of 5'-flanking sequence from the human a-lactalbumin gene including the a-lactalbumin promoter; (b) a DNA sequence encoding (1) a signal sequence; and (2) a-lactalbumin or a functional equivalent thereof; (c) at least about 3 kb of 3'-flanking sequence from the human a-lactalbumin gene the DNA construct being adapted to express the a-lactalbumin or functional equivalent thereof in a non-human transgenic animal.

In still a further aspect, the present invention provides a vector containing a recombinant DNA construct as defined above.

In further aspects the invention provides a host cell containing a vector as defined above, and a transgenic animal having a recombinant DNA construct as defined above integrated into its genome.

In a yet further aspect the present invention provides a-lactalbumin produced by expression of a recombinant expression system of the present invention, desirably such cx-lactalbumin produced in a transgenic mammal. The a-lactalbumin gene is naturally activated in the mammary glands of the lactating female mammal. Thus the protein expressed by the recombinant expression system of the present invention would be produced at WO 96/02640 PCT/GB95/01651 9 1 such a time and would be excreted as a milk component. 2 It may also be possible for the protein of interest to 3 be produced by inducing lactation through hormonal or 4 other treatment. Processed milk products comprising such a-lactalbumin are also covered by the present 6 invention. 7 8 In one preferred embodiment, the recombinant expression 9 system comprises a construct designated pHAl, pHA2, pBBHA, pOBHA, pBAHA, pBova-A or pBova-B. The 11 constructs pHAl, pHA2, pBBHA, pOBHA and pBAHA express 12 human a-lactalbumin and are thus preferred, 13 particularly pHA2. The construct pHA2 was deposited on 14 15 February 1995 at NCIMB under Accession No NCIMB 40709. 16 17 Likewise transgenic mammals comprising the specific 18 constructs listed above are preferred. 19 It has further been found tr.-at, in addition to 21 increased concentrations of j-lactalbumin per unit 22 volume of milk achieved by -he present invention, where 23 a human a-lactalbumin gene is present the volume of 24 milk produced increases also. This finding is totally unexpected and for this reason constructs containing 26 the human a-lactalbumin gene (or functional equivalents 27 or parts thereof) and transgenic animals (especially 28 cattle) are preferred embodiments of the invention. 29 3 0 Whilst we do not wish to be bound by theoretical 31 considerations, it is further believed that the 32 promoter region of the human a-lactalbumin gene is only 3 3 partially responsible for the enhanced natural 34 expression of a-lactalbumin by humans. It is believed that enhanced expression may be obtained by including 3 6 within the recombinant expression system of the present 37 invention the 3' sequence flanking the protein-encoding 38 region and/or the 5' sequence flanking the protein- SUBSTITUTE SHEET (RULE 26} WO 96/02640 PCT/GB95/016S1 1 encoding region itself. 2 3 The flanking sequences 3' and 5' to the protein- 4 encoding region of the human a-lac gene have been sequenced for the first time. Partial sequences 6 (nucleotides 1-264, 1331-2131, 2259-2496, 2519-2680 and 7 34 81-395?) of the 3' flanking region are presented in 8 SEQ ID Nos. 16 to 20 whilst the full sequence of the 5' 9 flanking region is presented in SEQ ID No. 21. In experiments it has been observed that inclusion of 11 either or both of these sequences give a surprisingly 12 marked increase in expression levels of the a- 13 lactalbumin protein. This increase in expression may 14 be observed when the protein-encoding region is nonr human a-lactalbumin as well as human a-lactalbumin. 16 17 Both the sequences of SEQ ID Nos. 16-20 and 21 are now 18 believed to contribute towards the higher levels of 19 expression of a-lactalbumin in human milk, and 2 0 therefore comprise a further aspect of the present 21 invention. 22 23 In a further aspect, the present invention provides a 24 polynucleotide having a sequence substantially as set out in any one of SEQ ID Nos. 16-20 or SEQ ID No. 21 or 26 a portion or functional equivalent thereof. 27 2 8 The polynucleotides may be in any form (for example DNA 29 or RNA, double or single stranded), but generally double stranded DNA is the most convenient. Likewise 31 the polynucleotides according to the present invention 32 may be present as part of a recombinant genetic 3 3 construct, which itself may be included in a vector 34 (for example an expression vector) or may be incorporated into a chromosome of a transgenic animal. 36 Any vectors or transgenic animals comprising a WO 96/02640 PCT/GB95/01651 11 1 polynucleotide as described above form a further aspect 2 of the present invention. 3 4 Viewed from a yet further aspect the present invention provides a recombinant expression system (preferably 6 adapted to express a-lactalbumin (preferably human a- 7 lactalbumin) or a portion or functional equivalent 8 thereof), said recombinant expression system comprising 9 a polynucleotide selected from the polynucleotide located between the EcoRI and Xhol restriction sites of 11 the wild-type a-lactalbumin gene and the polynucleotide 12 located between the BamHI and EcoRI restriction sites 13 of the wild-type human a-lactalbumin gene, or a portion 14 or functional equivalents thereof. 16 In one preferred embodiment, the recombinant expression 17 sequence of the present invention comprises both 18 polynucleotides as defined above, portions and 19 functional equivalents thereof. 21 The invention also encompasses vectors containing the 22 recombinant expression systems defined above and cells 23 transformed with such vectors. Further, the present 2 4 invention comprises transgenic animals wherein the transgene contains the recombinant expression system. 26 27 Figure 1 as discussed in Example 1 and shows the 2 8 sequence of bovine a-lactalbumin PCR primers. 29 Figure 2 is discussed in Example 1 and 4 shows the 31 position of bovine a-lactalbumin PCR primers and 32 products. 33 34 Figure 3 is discussed in Example 2 and shows a restriction map of two overlapping genomic A clones for 36 the human a-lactalbumin gene (pHA-2 and pHA-1).

WO 96/02640 PCT/GB95/01651 12 1 Figure 4 is discussed in Example 3 and shows a 2 restriction map of three overlapping genomic A clones 3 for the bovine beta-lactaglobulin gene. 4 Figure 5 is discussed in Example 4 and shows SDS-PAGE 6 analysis of skimmed milk from bovine a-lactalbumin 7 transgenic mice run against non transgenic mouse milk. 8 9 Figure 6 is discussed in Example 5 and shows human a- lactalbumin transgene constructs. 11 12 Figure 7 is discussed in Example 5 and shows SDS-PAGE 13 analysis of skimmed milk from human a-lactalbumin 14 transgenic mice run against non transgenic mouse milk. 16 Figure 8 is discussed in Example 5 and shows a Western 17 analysis of the milk from human a-lactalbumin 18 transgenic mice run against human a-lactalbumin 19 standard. 21 Figure 9 shows the PCR cloning strategy for transgene 22 constructs PKU1 to PKU4 as discussed in Example 6. 23 24 Figure 10 gives the sequences of PKU primers 1 to 10 as discussed in Example 6. 26 27 Figure 11 shows the structure of null and humanised a- 28 lactalbumin alleles. 29 Figure 12 is a Northern analysis of total RNA from a- 31 lactalbumin-deficient lactating mammmary glands. 32 33 Figure 13 illustrates a Western analysis of a- 34 lactalbumin from targeted mouse strains. 36 Figure 14 is a histological analysis of wild type and WO 96/02640 PCT/GB95/01651 13 1 a-lac" lactating mammary glands. 2 3 Figure 15A shows an RNase protection assay used to 4 distinguish human replacement and mouse a-lactalbumin mRNA and Figure 15B shows an RNase protection assay of 6 mouse and human replacement a-lactalbumin mRNA. 7 8 Figure 16 gives the quantification of a-lactalbumin by 9 hydrophobic interaction chromatography. 11 SEQ ID Nos. 16 - 20 give parts of the sequence from the 12 BamHI site to the vector restriction sites (including 13 EcoRI sites) 3' of the protein-encoding region of the 14 endogenous human a-lactalbumin gene, as set out below: 16 SEQ ID No. 16 : Nucleotides 1 to 264 (inclusive) Nucleotides 1331 to 2131 (inclusive) Nucleotides 2259 to 2496 (inclusive) Nucleotides 2519 to 2680 (inclusive) Nucleotides 3481 to 3952 (inclusive) 21 22 SEQ ID No. 21 gives the sequence from the EcoRI 23 restriction site to the Xhol restriction site which are 24 5' to the protein-encoding region of the endogenous human a-lactalbumin gene. 26 27 In mo're detail, in Figure 11 the upper portion shows 28 the wild type murine a-lactalbumin locus. The position 29 and direction of the transcribed region is indicated by the arrow. The translational stop site and RNA 31 polyadenylation sites are also indicated. The middle 32 portion shows the structure of the null allele. The 33 striped bar indictes the HPRT selectable cassette. The 34 lower portion shows the structure of the human replacement allele. The checkered bar shows the human 36 a-lactalbumin fragment. The transcription initiation, 17 SEQ ID No. 17 18 SEQ ID No. 18 19 SEQ ID No. 19 SEQ ID No. 20 WO 96/02640 PCT/GB95/01651 14 1 translational stop and polyadenylation sites are shown. 2 Restriction enzyme sites shown are: Hindlll (H); BamHI 3 (B); Xbal (X). 4 In Figure 12, the two autoradiographs shown are repeat 6 hybridisations of the same membrane filter using a 7 human a-lactalbumin probe followed by a rat ^-casein 8 probe. The probes used are indicated under each 9 autoradiograph. The source of RNA in each lane is indicated above the lane markers. 11 12 In Figure 13 Lane A contains purified human a- 13 lactalbumin. Lanes B-F show samples of milk from 14 targeted mice, genotypes are indicated above the lane markers. Lanes G and H are a shorter exposure of Lanes 16 C and D. 17 18 The light micrographs shown in Figure 14 are 19 haemtoxylin/eosin stained sections of mammary tissue (original magnification lOOx). The genotypes of each 21 gland are indicated. 22 23 In Figure 15A, the 3' junction between mouse and human 24 DNA in the a-lach allele lies between the translational stop site and the polyadenylation signal. Human a- 26 lactaibumin mRNA contains 120bp of mouse sequences in 27 the I' untranslated end. Human replacement and mouse 2 8 a-lactalbumin mRNA were detected by hybridisation with 29 a mouse RNA probe and distinguished by the size of RNA fragments protected from ribonuclease digestion. Human 31 sequences are indicated by the chequered bar and mouse 32 sequences by the shaded bar. Restriction enzyme sites 33 shown are: Hindlll (H); Bal (B); Xbal (X). 34 In Figure 15B the autoradiograph shown is of a 5% 36 polyacrylamide urea thin layer gel. The source of RNA WO 96/02640 PCT/GB95/01651 1 is indicated above the lane markers. Lane A shows a 2 wild-type RNA hybridised to the mouse RNA proe 3 undigested with ribonuclease. Lanes D to J show RNA 4 samples from a-lacm/a-lach heterozygotes, the numbers indicate individual mice and are the source of the 6 quantitative estimates given in Figure 15. The 7 predicted size of protected fragments are indicated. 8 9 The upper portion of Figure 16 shows phenyl-Sepharose elution profiles of three milk samples. 1, a-lach/a-lach 11 homozygote (mouse #22); 2, a-lac"7a-lach heterozygote 12 (mouse #76); 3, a-lacm/a-lacm wild type. The lower 13 portion shows a standard curve of known quantities of 14 human a-lactalbumin plotted against integrated peak area. 16 17 The present invention will now be further described 18 with reference to the following, non-limiting, 19 examples. 21 Example 1 - Cloninc; of Bovine a-lactalbumin gene 22 23 There are three known variants of bovine a-lactalbumin, 24 of which the B form is the most common. The A variant from Bos (Bos) nomadicus f.d. indicus differs from the 26 B variant at residue 10: Glu in A is substituted for 27 Arg in B. The sequence difference for the C variant 28 from Bos (Bibos) javanicus has not been established 29 (McKenzie & White, Advances in Protein Chemistry 41, 173-315 (1991). The bovine a-lactalbumin gene 31 (encoding the B form) was cloned from genomic DNA using 32 the PCR primers indicated in Figure 1. The primers 33 have been given the following sequence ID Nos: 34 Ba-2 SEQ ID No 1 Ba-7 SEQ ID No 2 36 Ba-8 SEQ ID No 3 WO 96/02640 PCT/GB95/01651 16 1 Ba-9 SEQ ID No 4 2 The source of DNA in all the PCR reactions was blood 3 from a Holstein-Friesian cow. 4 The length of the amplified promoter region using 6 primer Ba-9 in combination with primer Ba-8 is 0.72kb. 7 This BamHI/EcoRI fragment was cloned into Bluescript 8 (pBA-P0.7). 9 The length of the amplified promoter region using 11 primer Ba-7 in combination with primer Ba-8 is 2.Q5kb. 12 This BamHI/EcoRI fragment was cloned into Bluescript 13 (pBA-P2). 14 The entire bovine a-lactalbumin gene including 0.72kb 16 of 5' and 0. 3kb of 3' flanking region we.3 amplified 17 using primer Ba-9 in combination with primer Ba-2. 18 These primers include BamHI restriction enzyme 19 recognition sites, which allowed direct subcloning of the amplified 3kb fragment into the BamHI site of 21 pUC18, giving rise to construct pBova-A (see Figure 2). 22 23 Ligation of the BamHI/EcoRV fragment from clone pBA-P2 24 to the EcoRV/BamHI fragment of pBOVA-a gave rise to construct pBOVA-b (see Figure 2). 26 27 Since TAQ polymerase lacks proof-reading activity, it 28 was essential to ensure that the amplified bovine a- 2 9 lactalbumin DNA was identical to the published bovine a-lactalbumin gene. Sequence analysis was carried out 31 across all the exons and the two promoter fragments. 32 Comparison of the bovine a-lactalbumin exons with those 33 published by Vilotte showed 3 changes: 34 (i) Exon I at +759 C to A. 5' non-coding region; 36 (ii) Exon I at +792 CTA to CTG. Both code for Leucine 17 1 (iii) Exon II at +1231 GCG to ACG. Alanine to 2 Threonine 3 This is indicative of the more common "B" form of the 4 protein. 6 Although misreading of sequence during the PCR 7 amplification cannot be ruled out, the above mismatches 8 were probably due to the difference in the source of 9 bovine DNA. 11 Example 2 - Cloning of Human a-lactalbumin gene 12 13 The DNA sequences of human a-lactalbumin has been 14 published (Hall et al, Biochem. J., 242 : 735-742 (1987)). Using the human sequence, PCR primers were 16 designed to clone two small fragments from human 17 genomic DNA, one at the 5' end of the gene and the 18 other at the 3' end. These were subcloned into the 19 pUC18 vector and used as probes to screen a commercial 2 0 (Stratagene) A genomic library. Two recombinant 21 bacteriophages, 4a and 5b.1, which contained the a- 22 lactalbumin gene, were isolated by established methods 2 3 (Sambrook et al, Molecular Cloning 2nd ed. , Cold Spring 24 Harbor Laboratory (1989)). Restriction mapping demonstrated that both clones contained the complete 2 6 coding sequence for the human a-lac gene but differed 27 in the amount of 5' and 3' sequences present (Figure 28 3). Sequence analysis of exons from clone 5b.1 and 29 exons and 5' flanking region of clone 4a showed that these were identical to the published sequence. 31 32 Portions of the 3' sequence are given in SEQ ID Nos. 16 33 to 20 and the 5' sequence is given as SEQ ID No. 21. 34 Example 3 - Cloning of bovine beta lactoalobulin gene 36 (bBLG^ WO 96/02640 PCT/GB95/01651 18 1 The DNA sequence of bovine BLG (bBLG) has been 2 published (Jamieson et al; Gene, 61; 85-90, (1987); 3 Wagner, unpublished, EMBL Data Library: BTBLACEX 4 (1991)). Using the bovine sequence, PCR primers were designed to clone a fragment from the 5' portion of the 6 bovine BLG gene. This was subcloned into the pUC18 7 vector and used as probes to screen a commercial bovine 8 (Stratagene) A genomic library. Three genomic A clones 9 were isolated and characterised by restriction enzyme analysis (see Fig. 4). Two of the clones (BB13, BB17) 11 contain the complete bBLG coding region plus various 12 amounts of flanking regions, while clone BB25 lacks the 13 coding region and consists entirely of 5' flanking 14 region. Sequence analysis showed that the end of this clone lies 12 bp upstream of the ATG translation start 16 site. Sal I fragments containing the entire insert of 17 clone BB13 and BB17 were subcloned into pUClB, as well 18 as EcoR I fragments from clone BB25 (the latter was 19 cloned into pBluescript (Figure 4). 21 Example 4 - Assembly and expression of bovine ct- 22 lactalbumin constructs 23 24 Transoene constructs (Fig. 2^ 26 pBova-A consists of the bovine a-lactalbumin coding 27 region, =0.72kb of 5' flank and 0.3kb of 3' flank, 2 8 cloned as a 3kb BamHI fragment into Bluescript vector. 29 pBova-B consists of 3 fragments: 31 1. The 1.47kb BamHI to EcoRV fragment from clone pBA- 32 P2. 33 2. The 2.78kb EcoRV to BamHI fragment from clone 34 pBova-A. 3. The cloning vector Bluescript digested BamHI. 36 19 1 Bovine a-lactalbumin expression in transgenic mice 2 3 The two constructs pBova-A and pBova-B (Figure 2) were 4 injected into mouse embryos and gave rise to transgenic animals. Milk analysis by SDS-PAGE gel stained with 6 Coomasie blue (referred to as "Coomassie gels") and 7 comparison to standard amounts of a-lactalbumin showed 8 expression levels of bovine a-lactalbumin varied from 9 non detectable for pBova-A and up to =0.5-lmg/ml for 10 pBova-B (see Figure 5 and Table 1).

WO 96/02640 PCT/GB95/01651 1 Table 1 2 Bovine a-lactalbumin expression in transgenic mice 3 Mouse Coomassie 4 244.12 BOVA-a - 2 4 4.14 BOVA-a - 6 "7 244.15 BOVA-a - / 8 245.23 BOVA-b - 9 245.8 BOVA-b - 24 5.4 BOVA-b - 11 245.7 BOVA-b + 12 245.21 BOVA-b - 13 245.13 BOVA-b + 14 249.13 BOVA-b - 246.15 BOVA-b - 16 249.18 BOVA-b ++ 17 249.23.1 BOVA-b ++ 18 249.23.5 BOVA-b ++ 19 249.25.3 BOVA-b - 24 9.25.7 BOVA-b - 21 24 9.30.3 BOVA-b - = < 0.5mg/ml 22 24 9.30.4 BOVA-b + = =0.5-lmg/ml 23 24 9.33.2 BOVA-b +/++ ++ = =l-2mg/ml 24 249.33.3 BOVA-b +/++ 26 Table 1 shows the relative levels of bovine a- 27 lactalbumin in transgenic mouse milk as estimated by 28 comparison to protein standards on Coomassie gels.

WO 96/02640 PCT/GB95/01651 21 1 Example 5 - Assembly and expression of human a- 2 lactalbumin constructs 3 4 a-lactalbumin is the major whey protein in humans, beta-lactoglobulin the major whey protein in sheep and 6 cow. The level of a-lactalbumin expression varies from 7 species to species, human milk contains about 2.5mg/ml, 8 cow milk 0.5-1.Omg/ml, and mouse milk 0.1-0.8mg/ml. To 9 define sequences which allow maximum expression of the human a-lactalbumin gene several different constructs 11 were designed. These contain a) different amounts of 12 5' and 3' flanking regions derived from the human a- 13 lactalbumin locus, b) 5' flanking regions derived from 14 the bovine a-lactalbumin locus, or c) 5' flanking regions derived from the bovine or ovine beta- 16 lactaglobulin gene. The ovine beta-lactoglobulin gene 17 promoter has been successfully used to allow high 18 expression (>10mg/ml) of heterologous genes in mouse 19 milk. 21 Transgene constructs (Figure 6^ 22 23 pHA-1 consists of the human a-lactalbumin coding 24 region, =1.8kb of 5' flank and 3kb of 3' flank derived from A clone 5b.1 cloned as a 7kb EcoRI/Sall fragment 26 into pucl8. 27 2 8 pHA-2 consists of the human a-lactalbumin coding 29 region, =3.7kb of 5' flank and =13kb of 3' flank derived from A clone 4a cloned as a =19kb Sail fragment 31 into pucl8. 32 33 pOBHA (ovine beta-lactaglobulin, human a-lactalbumin) 34 was constructed from 4 DNA fragments: 1. a 4.2kb Sail/EcoRV fragment containing the ovine 36 beta-lactoglobulin promoter (see WO-A-9Q/05188 ); WO 96/02640 PCT/GB95/01651 22 1 2. a 74bp synthetic oligonucleotide corresponding to 2 a 8bp Bell linker and bases 15-77 of the human a- 3 lactalbumin sequence used as a blunt/Bgll 4 fragment; 3. a 6.2kb Bgll/PstI human a-lactalbumin fragment 6 derived from A clone 4a comprising a region 7 between a Bgll site at base 77 and a Xhol site in 8 the 3' flank; 9 4. pSL1180 (Pharmacia) cut with PstI and Sail. 11 pBBHA (bovine beta-lactoglobulin, human a-lactalbumin) 12 was constructed from 4 DNA fragments: 13 1. a 3.0kb EcoRI fragment containing the bovine beta- 14 lactoglobulin promoter derived from clone BB25-3 and used as a EcoRI/EcoRV fragment; 16 2. a 7 4bp synthetic oligonucleotide corresponding to 17 a 8bp Bell linker and bases 15-77 of the human a- 18 lactalbumin sequence used as a blunt/Bgll 19 fragment; 3. a 6.2kb Bgll/PstI human a-lactalbumin fragment 21 derived from A clone 4a comprising a region 22 between a Bgll site at base 77 and a Xhol site in 2 3 the 3' flank; 24 4. Bluescript vector cut with EcoRI and PstI. 26 pBAHA (bovine a-lactalbumin, human a-lactalbumin) was 27 constructed from 4 DNA fragments: 2 8 1. a 0.72kb BamHI to StuI fragment containing the 29 bovine a-lactalbumin promoter derived from clone pBA-PO.7; 31 2. a 62bp synthetic oligonucleotide corresponding to 32 bases 15-7 7 of the human a-lactalbumin sequence 33 used as a blunt/Bgll fragment; 34 3. a 6.2kb Bgll/PstI human a-lactalbumin fragment derived from A clone 4a comprising a region 36 between a Bgll site at base 77 and a Xhol site in WO 96/02640 PCT/GB95/01651 ► 1 the 3' flank; 2 4. Bluescript vector cut with BamHI and PstI. 3 4 Human a-lactalbumin expression in transgenic mice 6 5 constructs were injected into mouse embryos and gave 7 rise to transgenic animals. All constructs expressed 8 human a-lactalbumin in the milk of mice. pHA-1 and 9 pHA-2, which contain the human a-lactalbumin gene and various amounts of flanking regions expressed between 1 11 to =18mg/ml (213.5 pHA-2) in the majority of animals. 12 pOBHA and pBBHA containing the human a-lactalbumin gene 13 driven by either the ovine or bovine BLG promoter had 14 slightly lower levels of expression. pBAHA containing the human a-lactalbumin gene driven by the 0.72kb 16 bovine a-lactalbumin promoter had expression levels 17 similar to pHA-1 or pHA-2 but a lower percentage of 18 transgenic animals expressed detectable levels of 19 protein. This finding is surprising as the same bovine promoter sequence driving the bovine a-lactalbumin gene 21 gave very poor results (see Example 4 and Vilotte et 22 al; FEBS, Vol. 297, 1.2. 13-18 (1992)). 23 24 Table 2 gives a summary of the relative amount of the transgenic protein. Skimmed milk from these animals 26 was analysed by SDS-PAGE stained with Coomasie blue, 27 isoelectric focusing, Western blots visualised with a 2 8 commercial anti-human a-lactalbumin antibody (Sigma) 2 9 and chromatofocusing. The results from these analyses showed that the transgenic protein was of the correct 31 size, pi and antigenicity when compared to a human a- 32 lactalbumin standard (Sigma). 1 2 3 4 6 7 8 9 11 12 13 14 16 17 18 19 21 22 23 24 26 27 28 29 31 32 33 34 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 wo 96/02640 Table 2 Human a-lactalbumin expression in transgenic mice Mouse Coomassie Western 205.19 pHAl - — 204.10 pHAl ++ ++ 204.7 pHAl +++ +++ 230.15.3 pHAl +++ n.d. 230.15.5 pHAl +++ n.d. 230.15.6 pHAl +++ n.d. 230.21.5 pHAl +++ n.d. 2 30.21.1 pHAl ++ n.d. 211.18 pHA2 + ++ 211.1? pHA2 - - 211.16 pHA2 +++ +++ 212.11 pHA2 + n.d. 213.5 pHA2 ++++ ++++ 212.13 pHA2 ++ n.d. 212.19 pHA2 - n.d. 213.4 pHA2 +++ n.d. 212.7 pHA2 — n.d. 232.10 BBHA 233.1 BBHA - 231.4 BBHA ++ ++ 232.9 BBHA + + 231.9 BBHA - n.d. 232.5 BBHA + + 231.3 BBHA + + 232.6 BBHA - n.d. 2 37.6 BBHA - n.d. 235.15 OBHA _ n.d. 235.19 OBHA ++ ++ 236.6 OBHA ++ ++ 2 34.1 OBHA + + 234.4 OBHA ++ ++ 234.14 OBHA + + 239.14 BAHA +++ +++ 239.4 BAHA - n.d. 240.7 BAHA - n.d. 239.3 BAHA - n.d. 239.6 BAHA -f+ ++ 239.12 BAHA - n.d. 243.1 BAHA ++ n.d. 242.9 BAHA +++ n.d. 241.16 BAHA + n.d. 234.14 BAHA - n.d. 243.13 BAHA + n.d. 243.10 BAHA - n.d. 243.4 BAHA - n.d. 1 2 Table 2 shows the relative levels of human a- 3 lactalbumin in transgenic mouse milk as estimated by 4 comparison to protein standards on Coomassie gels and Western Blots. 6 7 8 + 9 ++ +++ 11 ++++ 12 n.d. 13 14 The results from several mice are shown in Figs. 7 and 8. Fig. 7 shows an SDS-PAGE analysis of skimmed 16 transgenic mouse milk run against a non-transgenic 17 control mouse milk. Fig. 8 shows a Western blot of 18 human a-lactalbumin transgenic milks run against a 19 human a-lactalbumin standard. 21 Example 6 - Expression of Mutaaenised Bovine a- 22 Lactalbumin under the control of the Human a- 23 Lactalbumin Promoter in vivo 24 Expression of the human a-lactalbumin transgene is 26 considerably higher than that of the native bovine a- 27 lactalbumin transgene, reflecting the difference in 28 expression levels of the endogenous bovine and human 29 genes. As this might be caused by differences in the 5' control region, the 5' region of the bovine a- 31 lactalbumin transcriptional start site was substituted 32 with sequences from the human a-lactalbumin gene. 33 34 Two constructs were made, namely PKU-5 and PKU-1H, which incorporate the amino acid substitutions shown in 36 Table 3. 37 <0.5 mg/ml = -0.5-lmg/ml = =1-2 mg/ml =2-3 mg/ml = >5 mg/ml = not determined WO 96/02640 PCT/GB95/01651 26 1 The following SEQ ID Nos. have been assigned to the PCR 2 primers used. 3 4 PKU-1 SEQ ID No.

PKU-2 SEQ ID NO. 6 6 PKU-2L SEQ ID No. 7 7 PKU-3 SEQ ID No. 8 8 PKU-4 SEQ ID No. 9 9 PKU-5 SEQ ID No.

PKU-6 SEQ ID No. 11 11 PKU-7 SEQ ID No. 12 12 PKU-8 SEQ ID No. 13 13 PKU-9 SEQ ID No. 14 14 PKU-10 SEQ ID No. 16 PKU-5 17 18 In a first cloning step three fragments were subcloned 19 into the EcoRI/BamHI site of pUC18: 21 (1) the EcoRI to Pvul fragment derived by PCR 22 amplification using PKU-primer 7 in combination 23 with 8 (see Figure 10); 24 (2) the Pvul to BsaBI fragment derived by PCR 26 amplification using PKU-primer 9 in combination 27 "with 10 (see Figure 10); and 28 29 (3) The BsaBI to Hindlll fragment derived from pBA. 31 The final construct included 6 DNA fragments: 32 33 (1) the 3.7kb Sail to Kpnl fragment containing the 34 human a-lactalbumin promoter derived from A clone 4a (Figure 3); 36 WO 96/02640 PCT/GB95/01651 27 1 (2) the 152bp synthetic oligonucleotide containing 2 human a-lactalbumin sequences from the Kpnl site 3 to the AUG and bovine a-lactalbumin sequences from 4 the AUG to the Hapl site; 6 (3) the 1.25kb Hpal to Hindlll fragment from the first 7 subcloning step; 8 9 (4) the 0.95 kb Hindlll to BgJlI fragment derived from pBA; 11 12 (5) the 3.7kb BamHI to Xhol fragment from the 3' flank 13 of the human a-lactalbumin gene derived from A 14 clone 4a (Figure 3) used as a BamHI fragment; and 16 (6) a Bluescript KS- vector cut with Sail and BamHI. 17 18 PKU-1H was constructed in the same way as PKU-5 with 19 the exception of fragment (3), which was derived from PKU-1. 21 22 PKU-1 was constructed from six DNA fragments (see 23 Figure 9): 24 (1) a 2.04kb SstI to Hpal fragment derived from 26 pBOVA-6; 27 2 8 (2) a 0.4 6kb Hpal to Pvul fragment derived from PCR 29 product A (PKU-primer pair 1 and 2; see Figure 10); 31 32 (3) a 0.60kb Pvul to BsaBI fragment derived from PCR 33 product B (primer pair 3 and 4; see Figure 10); 34 (4) a 0.22kb BsaBI to Hindlll fragment derived from 36 pBOVA-6; WO 96/02640 PCT/GB95/01651 1 (5) a 0.95kb Hindlll to Bglll fragment derived from 2 pBOVA-6; 3 4 (6) the vector pSL1180 digested with SstI and Bglll. 6 Table 3 7 8 Amino Acid Substitutions present in Transgene 9 Constructs 11 Substitutions Human promoter Plasmid 12 Human 3' flank 13 pos'n 9 30 53 80 14 Tyr, Tyr, Tyr, Tyr + pPKU-lH Ser, Tyr, Leu, Leu + pPKU-5 16 17 Expression in transgenic mice 18 19 The two constructs PKU-IH and PKU-5 have been injected into mouse embryos. So far transgenic animals were 21 derived for the PKU-5 construct. These animals are set 22 up for breeding to allow milk analysis. 23 24 Example 7 - Effect on Lactation bv disruption of a- Lactalbumin deficiency and insertion of human a- 26 Lactalbumin gene replacement in mice 27 2 8 Materials and Methods 29 Mouse lines 31 Mice carrying the null a-lactalbumin allele and the 32 humanised a-lactalbumin replacement allele were derived 3 3 by breeding chimeras produced from the targeted 34 embryonic stem cell clones M2 and F6 respectively against Balb/c mates, as described previously 36 (Fitzgerald et al J. Biol. Chem 245:2103-2108). During 29 1 the breeding of these strains, a-lactalbumin genotypes 2 were determined by Southern analysis of genomic DNA 3 prepared from tail biopsies. 4 RNA analysis 6 7 Total RNA was prepared by the method of Auffray and 8 Rougeon (Eur. J. Biochem 1^7:303-14) from abdominal 9 mammary glands of female mice 506 days postpartum.

Northern analysis was carried out according to standard 11 procedures (Sambrook et al, Molecular cloning). Probes 12 used for hybridisation were: a 3.5kb BamHI fragment 13 containing the complete mouse a-lactalbumin gene; and a 14 1. lkb rat /?-casein cDNA (Blackburn et al Nucl. Acids Res 10:2295-2307). 16 17 RNAse protection analysis 18 19 32P-CTP radiolabelled antisense RNA was transcribed by T7 RNA polymerase (Promega) from a 455 bp Hindlll-Ball 21 mouse a-lactalbumin fragment (Figure 15A) cloned in 22 Bluescript KS. The conditions for the transcription 2 3 reaction, solution hybridisation and RNAse digestion 24 were as recommended by Promega. Protected fragments were separated by polyacrylamide gel electrophoresis 26 and visualised by autoradiography. 27 28 Milk composition and yield analysis 29 Milk samples were collected between days 3-7 of 31 lactation under Hypnorm (Roche)/Hypnovel (Janssen) 32 anaesthesia. 150mU of oxytocin (Intervet) was 33 administered by intraperitoneal injection and milk 34 expelled by gentle massage. Milk fat content was measured as described by Fleet and Linzell (J. Physiol 36 17 5:15). Defatted milk was assayed for protein WO 96/02640 PCT/GB95/01651 1 (Bradford Analyt. Biochern 7.2 :248-54 ) and lactose was 2 measured enzymatically by sequential incubation with /?- 3 galactosidase, (Boehringer) glucose oxidase and 4 peroxidase (Sigma) by a method adapted from that of Bergmeyer and Bernt (Methods in Enzyme Analysis 3.: 1205- 6 1212). 7 8 Milk yield was estimated using a titrated water 9 technique described by Knight et al. , (Comp. Biochern.

Physiol 84A:127-133) in mice suckling young over a 48 11 hour period between days 3 and 6 of lactation. 12 13 Milk ct-lactalbumin analysis and quantification 14 Milk samples were analysed on 16% of SDS-PAGE gels 16 (Novex) and western blotted onto Immobilon P membrane. 17 a-lactalbumin was detected by absorption with rabbit 18 anti-human a-lactalbumin antiserum (Dako), followed by 19 goat anti-rabbit IgG peroxidase antibody conjugate and visualised with an enhanced chemiluminescence system 21 (Amersham). 22 23 a-lactalbumin in milk samples was quantified by a 24 modification of the method of Lindahl et al., (Analyt.

Biochern 140:394-402) for calcium dependant purification 2 6 of a-lactalbumin by phenyl-Sepharose chromatography. 27 Milk'samples were diluted 1:10 with 27% w/v ammonium 28 sulphate solution, incubated at room temperature for 10 2 9 minutes and centrifuged. Supernatant was mixed with an equal volume of lOOmM Tris/Cl, pH 7.5, 7 0mM EDTA and 31 loaded onto a column (200^1 packed volume) of phenyl- 32 Sepharose (Pharmacia) pre-equilibrated with 50mM 3 3 Tris/Cl, pH 7.5, ImM EDTA. The column was washed with 34 the same buffer and a-lactalbumin eluted with 50mM Tris/Cl, pH 7.5, ImM CaCl2- The optical absorbance at 36 2 80nm of the column was monitored and integrated peak WO 96/02640 PCT/GB95/01651 31 1 areas corresponding to the a-lactalbumin fraction 2 computed. A standard curve was constructed using known 3 quantities of purified human a-lactalbumin from 0 to 4 2.46 mg/ml (Figure 16). 6 Histology 7 8 Pups were removed for two hours from lactating mothers 9 on the sixth day postpartum, mothers sacrificed and thoracic mammary glands were dissected, preserved in 11 neutral buffered formalin, paraffin embedded and 12 stained with haematoxylin/eosin by standard methods. 13 14 Results 16 Mouse a-lactalbumin gene deletion 17 18 A line of mice in which a 2.7kb fragment covering the 19 complete mouse a-lactalbumin coding region and a 0.57kb of promoter has been deleted and replaced with a 2.7kb 21 fragment containing a hypoxanthine phosphoribosyl- 22 transferase (HPRT) selectable marker gene was 23 established as described in Stacey et al, 1994 supra 24 (see Figure 11). Animals carrying this allele are designated a-lac-. The wild type mouse a-lactalbumin 26 allele is designated a-lac™. 27 2 8 Northern analysis of RNA from mammary glands taken on 29 the fifth day of lactation showed that a-lactalbumin mRNA was absent in a-lac-/a-lac- homozygotes (see 31 Figure 12) confirming that the targeted a-lactalbumin 32 gene has been removed and that no other source of a- 33 lactalbumin mRNA exists. Hybridisation of the same RNA 34 samples with a /?-casein RNA in all samples (see Figure 12). 36 WO 96/02640 PCT/GB95/01651 32 1 a-Lacta) bum.in deficiency has no apparent effect in mice 2 other than during lactation. a-lac-/a-lac- homozygotes 3 and a-lacVa-lac-heterozygotes of both sexes are normal 4 in appearance, behaviour and fertility. However, a- lac-/a-lac- homozygous females cannot rear litters 6 successfully. Their pups fail to thrive and die within 7 the first 5-10 days of life. Offspring of homozygous 8. a-lac-/a-lac- females do survive normally when 9 transferred to wild type foster mothers. Conversely, offspring from wild type mothers transferred to 11 homozygous a-lac-/a-lac- mothers are not sustained. 12 Table 4 shows that pups raised by a-lac-/a-lac- mothers 13 are approximately half the weight of those raised by a- 14 lacm/a-lacm wild type mice. Estimates of milk yield are consistent with this, a-lacVa-lac- heterozygotes 16 produce similar quantities of milk as wild type, but 17 the yield of a-lac-/a-lac- homozygotes was severely 18 reduced (Table 4).

Table 4 Milk composition, pup weight, mammary tissue weight and milk yield in targeted mouse lines Genotype a-lacm/ot-lacm a-lacm/cx-lac- a-lac-/cx-lac- a.- lac"/ot— lach a-lach/ot-lach Fat ( % v/v) 28.23 + 1.65(7) 29.6 ± 1.3(6) 45.25 ± 2.15(6)*** .25 + 1.36(7) 21.2 + 0.23(4)* Protein (mg/ml) 87.52 + 5.82(7) 95.81 ± 9.5(5) 164.63 + 13.92(8)*** 94.51 + 5.97(7) 77.07 ± 1.05(4) Lactose (mM) 62.44 + 9.27(7) 42.7 + 4.2(6) 0.7 ± 0.34(3)*** 42.40 ±1.93(7) 56.85 t 3.8(4) Single pup weight (g) 2.82 ± 0.25(8) 3.14 ± 0.1(7) 1.52 ± 0.12(10)*** 2.9 ± 0.15(8) 3.4 ± 0.75(4) Mammary tissue weight per pup (g) 0.34 i 0.06(7) 0.4 + 0.1(7) 0.35 ± 0.05(8) 0.31 ± 0.04(6) 0.51 ± 0.09(4) Milk yield (g/day) 7.51 ± 0.44(4) 6.7 + 0.38(6) 1.37 ± 0.48(4)*** n. t. 9.94 + 0.65(5)* Statistical analysis by unpaired t-test, * p<0.05; **p<0.01; ***p<0.001; Values are means t SE.

Figures in brackets indicate the number of mothers analysed. n.t., not tested WO 96/02640 , PCT/GB95/01651 3 A 1 Milk was obtained from each genotype by manual milking 2 and the composition of key components analysed. Milk 3 from a-lacVa-lac-heterozygotes was indistinguishable in 4 appearance from wild type milk and showed fat and protein contents similar to wild type (Table 4). While 6 lactose concentration appeared to be slightly reduced 7 in a-lacVa-lac- heterozygotes, statistical analysis 8 showed that the difference was not significant. In 9 contrast, milk from a-lac-/a-lac- homozygotes was viscous, difficult to express from the teats and was 11 markedly different in composition to wild type. Fat 12 content was -60% greater than wild type, protein content 13 was -88% greater, and lactose was effectively absent. 14 The apparent 0.7mM lactose detected in a-lac-/a-lac- females represents milk glucose content, since the 16 lactose assay used involved the enzymatic conversion of 17 lactose to glucose. Direct assay of glucose in wild 18 type milk indicated a concentration of 1.8mM. 19 Western analysis of milk protein failed to detect a- 21 lactalbumin in milk from a-lac-/a-lac- homozygotes (see 22 Figure 13, Lane F). This was confirmed by phenyl-2 3 Sepharose chromatography, a technique used to 24 specifically identify a-lactalbumin which has been adapted to obtain quantitative estimates of milk a- 26 lactalbumin content (Table 5; see also Figure 16). 27 When.applied to milk from a-lac-/a-lac-homozygotes no 2 8 a-lactalbumin was detected. In contrast, a-lactalbumin 2 9 concentration in a-lacm/a-lac- heterozygote milk was estimated as 0.04 3mg/ml, approximately half that of 31 wild type (Table 5). 1 Table 5 2 Milk a-lactalbumin content. 3 4 Source Human 6 a-lacVa-lac" mice 7 a-lac-/a-lac-mice 8 a-lac'Va-lac-mice 9 a-lac"/a-lach mice a-lach/a-lach mice 11 12 a-Lactalbumin content of milk samples were estimated by 13 phenyl-Sepharose chromatography. 14 Values are means ± SE. 16 17 Figures in brackets indicate the number of mothers 18 analysed. 19 a-Lactalbumin deficiency has no apparent effect on 21 mammary gland development. Table 4 shows that total 22 mammary tissue weights of wild type, heterozygous a- 23 lacm/a-lac- and homozygous a-lac-/a-lac- lactating 24 mothers were not significantly different. Light microscopic analysis of mammary glands (Figure 14) 26 revealed that heterozygous and homozygous a-lac-/a-lac- 27 glands were histologically normal. However, the 2 8 alveoli and ducts of homozygous glands were distended 29 and clogged with material rich in lipid droplets. 31 Replacement of mouse a-lactalbumin by human a- 32 lactalbumin 33 34 We have generated mice carrying the human a-lactalbumin gene at the mouse a-lactalbumin locus. The 2.7kb mouse 36 a-lactalbumin fragment deleted at the a-lac- null 37 allele was replaced by a 2.97kb fragment containing the 38 complete human a-lactalbumin ceding region and 5' g-lactalbumin (ma/ml) 2.9 + 0.1(2) 0.09 i 0.005(6) 0 (3) 0.043 + 0.004(5) 0.65 ± 0.07(4) 1.38 + 0.12(5) WO 96/02640 36 PCT/GB95/01651 1 flanking sequences. The human fragment stretches from 2 0.77kb upstream of the human transcription initiation 3 site to an EcoRI site 136bp 3' of the human 4 translational stop site. Junctions with mouse sequences were made at a BamHI site 0.57kb upstream of 6 the mouse transcription initiation site and at an Xbal 7 site 147bp 3' of the mouse translational stop site (see 8 Stacey et al, 1994, supra; see also Figure 11). Here 9 we describe our analysis of animals carrying this allele, designated a-lach. 11 12 Deletion of the murine a-lactalbumin gene established 13 that a-lactalbumin deficiency blocks lactose synthesis 14 and severely disrupts milk production. We have used the a-lach allele to test the ability of human a- 16 lactalbumin to restore milk production in the absence 17 of mouse a-lactalbumin. a-lac°/a-lach heterozygous and 18 a-lach/a-lach homozygous mice were normal in appearance, 19 fertility and behaviour. 21 In contrast to a-lac-/a-lac- mice, a-lach/a-lach 22 homozygous mothers produce apparently normal milk and 23 rear offspring successfully. Table 4 shows that pups 24 raised by a-lactt/a-lach heterozygous and a-lach/a-lach homozygous females are similar in weight to those of 26 wild type mothers. This is supported by our 27 observation that these animals raised successive 28 litters of pups entirely normally. These data 2 9 constitute clear evidence that the human gene can functionally replace the mouse gene. Analysis of milk 31 composition (Table 4) shows that lactose concentration 32 is similar in all genotypes. Although both protein and 33 fat concentrations seem reduced in a-lach/a-lach 34 homozygous animals, only the fat reduction was judged statistically significant by unpaired t-test. These 36 animals show an increase in milk volume over wild type 37 (Table 4) . 38 37 PCT/GB9S/01651 1 Relative quantification of human and mouse a- 2 lactalbumin RNA. 3 4 Human milk contains considerably more a-lactalbumin (2.5mg/ml) than murine milk (O.lmg/ml). We wished to 6 determine whether the human a-lactalbumin fragment 7 retained a high level of expression when placed at the 8 mouse locus, or assumed a lower level more S characteristic of the mouse gene. a-lacVa-lach heterozygous mice provided an ideal means of addressing 11 this question, as the expression of the human gene 12 could be directly compared with its mouse counterpart 13 in the same animal. 14 Figure 15A shows the strategy used to compare levels of 16 mouse and human a-lactalbumin mRNA. Because the 17 junction between human and mouse a-lactalbumin 18 sequences lies upstream of the polyadenylation site, a- 19 lach mRNA contains a "tag" of 120 bases of untranslated mouse sequences at the 3' end. A uniformly 21 radiolabelled mouse RNA probe was used in a 22 ribonuclease protection assay to detect and distinguish 23 human and mouse a-lactalbumin mRNA in the same RNA 24 sample. The relative abundance of each mRNA was calculated from the amount of label in fragments 26 protected by human and mouse mRNAs. 27 28 A ribonuclease protection assay was performed and the 29 results are shown in Figure 15B. Lane A shows the undigested 455 base probe and Lane K shows that yeast 31 tRNA did not protect any fragments. Wild type mouse 32 RNA protected a fragment consistent with the predicted 33 305 base RNA from endogenous mouse a-lactalbumin RNA 34 (see Lane B) . Homozygous a-lach/a-lach gland RNA protected a smaller band consistent with the predicted 36 120 base RNA protected by human a-lactalbumin mRNA (see 37 Lane C). Lanes D-J show results consistent with a 38 series of heterozygous a-lac"7a-lach animals were 1 2 3 4 6 7 8 9 11 12 13 14 38 PCT/GB9S/01651 obtained (seo Lanes D to J). Small and large protected fragments in ^ach sample indicate the presence of both human and mouse a-lactalbumin mRNA. Protected fragments were excised from the gel, radioisotope content measured, adjusted for the size difference and the ratio of human to mouse a-lactalbumin mRNA estimated. Table 6 shows the amount of radioisotope present in the 305 base and 120 base fragments excised from Lanes D to J of the gel shown in Figure 15B, and the calculated ratio of human to mouse a-lactalbumin mRNA in each a-lacn/'a-lach heterozygote. It is apparent that, although there was variation between individual animals, human a-lactalbumin mRNA was significantly more abundant than mouse mRNA. Averaging the seven a-lacm/a-lach heterozygotes gives a value of 15-fold greater expression for human a-lactalbumin mRNA. 39 1 2 3 4 6 7 8 9 11 12 13 14 16 17 18 19 21 22 23 24 26 27 28 29 31 32 33 34 Table 6 Relative quantification of human and mouse a-lactalbumin mRNA in a-lac°/a-lach mammary glands Lane Mouse# 2 3 120 base 305 base human/mouse fragment3 fragment" RNA ratiob H 76 98 99 79 5957 5770 4825 6018 5206 5481 26858 1000 547 810 1077 1452 1117 3561 :1 26:1 15:1 14:1 9:1 12:1 19:1 Lane designations indicate the source of protected fragments and correspond to those shown in Figure 15B. a. numbers are expressed in counts per minute (c.p.m.) b. Ratio between c.p.m. of 120 base fragment multiplied by 2.54 (to adjust for size difference) and c.p.m. of 305 base fragment.

WO 96/02640 PCT/GB95/01651 1 Human a-lactalbumin protein expression 2 3 A Western analysis of a-lactalbumin in targeted mouse 4 lines was conducted. Human a-lactalbumin can be distinguished from mouse a-lactalbumin by its faster 6 electrophoretic mobility (see Lanes A, B). A prominent 7 lower band in a-lach/a-lach homozygotes and a-lach/a-lacm 8 heterozygotes was observed (see Lanes C, D, G, H), and 9 corresponds to the position of the human a-lactalbumin standard and was only observed in mice which express 11 human a-lactalbumin generated either by gene targeting 12 or by pronuclear microinjection (data not shown). This 13 identity was confirmed by phenyl-Sepharose 14 chromatography (See Figure 16) and analysis of peptides released by cyanogen bromide cleavage (data not shown). 16 The band with slower mobility, similar to mouse a- 17 lactalbumin, is also a human a-lactalbumin gene product 18 the nature of which is unknown. This species varied in 19 intensity with a-lach gene dosage (see Lanes G, H) and 2 0 was also present in milk from human a-lactalbumin 21 transgenic mice generated by pronuclear microinjection 2 2 (data not shown). 23 2 4 The a-lactalbumin content of milk samples was quantified by phenyl-Sepharose chromatography. Figure 26 16 shows superimposed absorbance profiles of column 27 eluates of three illustrative milk samples including 2 8 the a-lac"/a-lach heterozygote and a-lach/a-lach 29 homozygote shown in Figure 13. The peaks corresponding to eluted a-lactalbumin are marked. a-Lactalbumin 31 contents were estimated by comparing the integrated 32 peak areas with the human a-lactalbumin standard curve 33 shown. The relationship between integrated peak area 34 and a-lactalbumin quantity was linear and highly reproducible. a-Lactalbumin content for the samples 36 • shown in Figure 16 were estimated as follows: a-lacVa- 37 lacm wild-type O.lmg/ml; a-lac°'/a-lach heterozygote #76 38 0.45mg/ml; a-lach/a-lach homozygote #22 0.9mg/ml. Table WO 96/02640 .. PCT/CB95/01651 1 5 shows the concentration of a-lactalbumin in milk 2 samples from targeted mouse lines and lactating women. 3 It is clear that the concentration of a-lactalbumin in 4 milk is directly related to gene dosage, eg a-lac°/a- lac- heterozygotes shown an a-lactalbumin concentration 6 half that of wild type. Given that the volumes of milk 7 produced by these mice are similar (Table 4), the 8 concentration of a-lactalbumin provides a reasonable 9 indication of the quantity synthesised. The relative proportions of human and mouse a-lactalbumin components 11 in a-lacm/a-lach heterozygote milk were estimated by 12 assuming that a-lactalbumin expression from a single 13 mouse allele was 0.043mg/ml and the rest represented 14 human a-lactalbumin. This is consistent with the amounts of a-lactalbumin expressed by a-lacn/a-lac- 16 heterozygotes and wild type mice. Therefore, a-lacVa- 17 lac-heterozygotes were estimated as expressing 18 0.61mg/ml human and 0.043mg/ml mouse a-lactalbumin. 19 Thus, human a-lactalbumin is approximately 14-fold more abundant than mouse a-lactalbumin in a-lacVa-lach 21 heterozygote milk. This is remarkably consistent with 22 the relative proportions of mRNA. 23 24 Example 8 Enhanced expression of a heterologous crene. 26 These data confirm that the upstream promoter region 27 (AUG.to about -3.7 kb) which is included in the pHA-2 28 construct enhances expression of a heterologous gene. 29 Table 7 shows the results of milk analysis from pHA-2 transgenic founder females. Out of 10 females, 6 31 animals expressed high levels of human a-lac. 3 32 animals failed to express detectable levels of human a- 33 lac (less than 0.2 mg/ml in this assay), all 3 also 34 failed to transmit the transgene. We can neither be certain whether they were low expressors or not 36 transgenic. 37 WO 96/02640 k2 PCT/GB9S/01651 1 Table 8: Constructs PKU-0 to BALT-B all contain the 2 bovine a-lac promoter (about 2kb) . Constructs PKU-IH 3 to PKU-16 all contain the human a-lac promoter (3.7kb). 4 Using the human a-lac promoter increased the expression of the transgene to almost 100%. 6 7 These data show that the use of the human a-lac 8 promoter achieves a higher level of expression than the 9 use of the bovine promoter, and induces expression in 10 more animals than the bovine promoter.

TABLE 7 CONSTRUCT MOUSE SEX C mg/ml MILK ANALYSIS TRANS.

MI FREQ. pHA2 210-17 M - — 1/21=5% 211-12 F <1 - - 14/54 = 26% 211-16 F 3/4 211-17 F >>10 ND 0/8 211-24, 27, 29, 31, 36, 37, 42, 46, 47, 54 M 212-7 F ND 0/5 8/77=10% 212-11 F <10 1 0/4 212/13 F >1 1-5 2/4 - 212-19 F >10 ND 0/8 212-36, 44, 45, 46 M 213-4 F <10 0/2 2/14=14% 213-5 F >10 2/8 OVERALL MIF 25/166=15% ND = Not detectable TBA = To be analysed TBO = To bred on C = Copy number TRANS. = Transmission MI FREQ. = Integration frequency A3 TABLE 8 Constr.

Transgenics Expressers max. expr.

PKU-0 6F/5M 3/5 500 PKU-1 18F/23M /18 200 PKU-2 8F/7M 3/8 400* PKU-3 6F/5M 2/6 100* PKU-4 7F/3M /18 300* BALT-A 34F/24M n.t. n.t.

BALT-B 10F/18M n.t. n.t.

PKU-IH 6F/5M 4/5 100 PKU-5 13F/14M 13/13 800 PKU-6 3F/4M 2/2 100 PKU-7 4F/11M 1/1 <20 PKU-16 13F/12M n.t. n.t.

HctPKU-1 n.t. n.t. n.t.

HaPKU-2 n.t. n.t. n.t. n.t. = not tested * estimate hh sequence: listing (1) GENERAL INFORMATION: (i) APPLICANT: (A) NAME: PPL THERAPEUTICS (SCOTLAND) LIMITED (B) STREET: ROSLIN (C) CITY: EDINBURGH (E) COUNTRY: UNITED KINGDOM (F) POSTAL CODE (ZIP): EK25 ir't (ii) TITLE OF INVENTION: Alpha-lactalbumin Gene Constructs (iii) NUMBER OF SEQUENCES: 21 (iv) COMPUTER READABLE FORM: (A) MEDIUM TYPE: Floppy disk (B) COMPUTER: IBM PC compatible (C) OPERATING SYSTEM: PC-DOS/MS-DOS (D) SOFTWARE: Patentln Release #1.0, Version #1.30 (EPO) (2) INFORMATION FOR SEQ ID NO: 1: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 27 base pairs (3) TYPE: nucleic acid (C) STRANDEDNESS: single (D) TOPOLOGY: linear (ii) MOLECULE TYPE: cDNA (xi) SEQUENCE DESCRIPTION: SEQ ID NO: 1: GCGGATCCAC AACTGAAGTG ACTTAGC 27 (2) INFORMATION FOR SEQ ID NO: 2: (:') SEQUENCE CHARACTERISTICS: (A) LENGTH: 35 base pairs (B) TYPE: nucleic acid (C) STRANDEDNESS: single (D) TOPOLOGY: linear (ii) MOLECULE TYPE: cDNA (Xi) SEQUENCE DESCRIPTION: SEQ ID NO: 2: SUBSTITUTE SHEET (RULE 26)' (xi) SEQUENCE DESCRIPTION: SEQ ID MO: 3: GCAGGCGAAT TCCTCAAGAT TCTGAAATGG GGTCACCACA CTG (2) INFORMATION FOR SEQ ID NO: 4: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 33 base pairs (3) TYPE: nucleic acid (C) STRANDEDNESS: single (D) TOPOLOGY: linear (ii) MOLECULE TYPE: CDNA (xi) SEQUENCE DESCRIPTION: SEQ ID NO: 4: GAGGATCCAA TGTGGTATCT GGCTATTTAG TGG (2) INFORMATION FOR SEQ ID NO: 5: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 4o base pairs (B) TYPE: nucleic acid (C) STRANDEDNESS: single (D)-TOPOLOGY: linear (ii) MOLECULE TYPE: cDNA (xi) SEQUENCE DESCRIPTION: SEQ ID NO: 5: GCTGAATTCG TTAACAAAAT GTGAGGTGTA TCGGGAGCTG AAAGAC 4 6 (2) INFORMATION FOR SEQ ID NO: 6: 45 GATGGATCCT GGGTCCTCAT TGAAAGGACT GATCC (2) INFORMATION FOR SEQ ID NO: 3: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 43 base pairs (B) TYPE: nucleic acid (C) STRANDEDNESS: single (D) TOPOLOGY: linear (ii) MOLECULE TYPE: cDNA SUBSTITUTE SHEET (RULE 26) 46 (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 58 base pairs (3) TYPE: nucleic acid (C) STRANDEDNESS: single (D) TOPOLOGY: linear (ii) MOLECULE TYPE: cDNA (xi) SEQUENCE DESCRIPTION: SEQ ID NO: 6: GCGCATCCGA TCGCTTGTGT GTCATAACCA CTGGTATGGT ACGCGGTACA GACCCCTG 58 (2) INFORMATION FOR SEQ ID NO: 7: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 58 base pairs (3) TYPE: nucleic acid (C) STRANDEDNESS: single (D) TOPOLOGY: linear (ii) MOLECULE TYPE: cDNA (xi) SEQUENCE DESCRIPTION: SEQ ID NO: 7: GCGGATCCGA TCGCTTGTGT GTCATAACCA CTGCTATGGA GCGCGGTACA GACCCCTG 58 (2) INFORMATION FOR SEQ ID NO: 8: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 69 base pairs (3) TYPE: nucleic acid (C) STRANDEDNESS: single (D) TOPOLOGY: linear (ii) MOLECULE TYPE: CDNA (xi) SEQUENCE DESCRIPTION: SEQ ID MO: S: GCGGATCCGA TCGTACAAAA CAATGACAGC ACAGAATATG GACTCTACCA CATAAATAAT 60 AAAATTTGG 69 (2) INFORMATION FOR SEQ ZD NO: 9: I (i) SEQUENCE CHARACTERISTICS: SUBSTITUTE SHEET (RULE 26) 47 (A) LENGTH: 34 base pairs (B) TYPE: nucleic acid (C) STRANDEDNESS: single (D) TOPOLOGY: linear (ii) MOLECULE TYPE: cDNA (xi) SEQUENCE DESCRIPTION: SEQ ID NO: 9: GCTCTAGATC ATCATCCAGG TACTCTGGCA GGAG 34 (2) INFORMATION FOR SEQ ID NO: 10: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 24 base pairs (3) TYPE: nucleic acid (C) STRANDEDNESS: single (D) TOPOLOGY: linear (ii) MOLECULE TYPE: cDNA (Xi) SEQUENCE DESCRIPTION: SEQ ID NO: 10: GCTGAAGCTT CACTTACTTC ACTC 24 (2) INFORMATION FOR SEQ ID NO: 11: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 65 base pairs (B) TYPE: nucleic acid (C) STRANDEDNESS: single (D) TOPOLOGY: linear (ii) MOLECULE TYPE: cDNA (xi) SEQUENCE DESCRIPTION: SEQ ID NO: 11: GCGGATCCAA AGACAGCAGG TGTTCACCGT CGACGACGCC TACGTAACTT CTCACAGAGC 60 CACTG 65 (2) INFORMATION FOR SEQ ID NO: 12: 1 (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 46 base pairs SUBSTITUTE SHEET (RULE 26) 48 (3) TYPE: nucleic acid (C) STRANDEDNESS: single (D) TOPOLOGY: linear (ii) MOLECULE TYPE: cDNA (xi) SEQUENCE DESCRIPTION: SEQ ID NO: 12: CCTGAATTCG TTAACAAAAT GTGAGGTGAG CCGGGAGCTG AAAGAC (2) INFORMATION FOR SEQ ID NO: 13: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 54 base pairs (B) TYPE: nucleic acid (C) STRANDEDNESS: single (D) TOPOLOGY: linear (ii) MOLECULE TYPE: cDNA (xi) SEQUENCE DESCRIPTION: SEQ ID NO: 13: GCGGATCCGA TCGCTTGTGT GTCATAACCA CTGGTATGAT ACGCGGTACA GACC (2) INFORMATION FOR SEQ ID NO: 14: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 69 base pairs (3) TYPE: nucleic acid (C) STRANDEDNESS: single (D) TOPOLOGY: linear (ii) MOLECULE TYPE: cDNA (xi) SEQUENCE DESCRIPTION: SEQ ID NO: 14: GCGGATCCGA TCGTACAAAA CAATGACACC ACAGAATATG GACTCCTCCA GATAAATAAT 60 aaaatttgg gg (2) INFORMATION FOR SEQ ID NO: 15: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 34 base pairs (C) TYPE: nucleic acid SUBSTITUTE SHEET (ROLE 26) WO 96/02640 PCT/GB95/01651 49 (C) STRANDEDNESS: single (D) TOPOLOGY: linear (ii) MOLECULE TYPE: cDNA (xi) SEQUENCE DESCRIPTION: SEQ ID NO: 15: GCTCTAGATC ATCATCCACC AGCTCTGGCA GGAG 34 (2) INFORMATION FOR SEQ ID NO: IS: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 264 base pairs (B) TYPE: nucleic acid (C) STRANDEDNESS: double (D) TOPOLOGY: linear (ii) MOLECULE TYPE: CDNA (xi) SEQUENCE DESCRIPTION: SEQ ID NO: 16: GGATCCAAAG TTGGCTAAAC ACTGGCCGGG TGCAGTGCTT CCACCTGTAA TTCCAGCACT 60 TTGGAAGGCT GAGGTGGGCA GATTGCTTGA GC-TCAGGAGT TTGAGACCAG CTTGGCTAAC 120 AGCAAAACCC TGTCTCTACC AAAAGTACAA AAATTATCTG GGTGTGGTGG CAGGCGCCTG 180 TAATCCCAGC TACTCGGGAG GCTGAGGCAG AAGAATTGTT TGAACCTGGG AGGCAGAGGT 2 40 TGTAGTGAGC TGAGATCGCT CATT 264 (2) INFORMATION FOR SEQ ID NO: 17: (i) SEQUENCE CHARACTERISTICS: (n) LENGTH: 803 base pairs (B)" TYPE: nucleic acid (C) STRANDEDNESS: double (D) TOPOLOGY: linear (ii) MOLECULE TYPE: cDNA (xi) SEQUENCE DESCRIPTION: SEQ ID NO: 17: TCTTTTTCAA TTATTCATTT GTTACAGTGG GTTATGATAC AAATGTTTAT AGATGCCTAC 60 SUBSTITUTE SHEET (RULE 26) WO 96/02640 PCT/GB95/01651 50 TC7GTAC7AG TACTACAGAG CACTTT7TCT GTGTTTATAT TCAGTTCAAT TGTAGTGTGT 120 TGAGTTGTAT WWTAATCCAT GTATTAAATC AAATAAACAA ACAAAATGCC ATGTTCTTTG 180 GTACAAGCAA CACTCACCAA AGGCATTTGG GGTCTGCATT TGGAATTCTC AGGCAAACTC 240 TCTCTTGTTC CTAGTCTGTA C77A777TCC CCACACTAGC T7A7G7ATAT ATATTTTTGA 300.

GAT7GGAGTT GCCCTTGTTG CCCAGGCTGG AGTGCAGTGG CACGATTCTT GGCTCACGAG 360 ACCTCCACGT CTTGGGTTAA AGCGTTTCTC CTGCCTCACC CTCCTGACTA CTGGGATTAC 420 AGGCGCCTGC CACCA7GCCC GGCTAA777T TGTAT7777A GTAGAGA7GG GCT77CACCA 480 TG7TGCTCAG GCTGG7CTTG AAACTCCCCA CCTCGGCCC7 TCCCAAATGC GCTGGGATTA 540 CAGG7GTGAG CCACAGTGCC TGGCCTGTAC A7T7TTTAAA T7TCAA7GTC 7AATATGGTG 600 TCCAC7GAAT TAAGAATTC7 77TGAGAAAA TGAA7CAA7A AATC7A7ACA CTGCCTCCTT 660 7ATCCAG7GA GGTATGGCTG GA7CAGCT7C A 7 G A C AT A C A 7GCCAGTAGT TCTCCTCCTC 720 CTCCTTTT7T ACAAATAAAA ATTG7ATA7G T7GAAGG7G7 ACAAC77GAT GTTTG7TATA 780 TG7ATACACT TAAATGTCAC CAC 303 (2) INFORMATION FOR SEQ ID NO: 18: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 233 base pairs (B) TYPE: nucleic acid (C) STRANDEDNESS: double (D) TOPOLOGY: linear (ii) MOLECULE TYPE: cDNA (xi) SEQUENCE DESCRIPTION: SEQ ID NO: 18: TTTGGGTAGA AGCAGACAGT AAACTTGCTG TTCTCTTCCT GAGATCTTTT GTTGAGATGC 60 TGAATAGGAG GCAGCATGGC AGCTGAGCTA TCTGTTCTGC T77C7C7ACC TCTGTCTCTT 120 TCCCTTAGGC CTAAAATGAA GCTCTAAGCC AAGCAAAGG7 C7GAAGTCAT CCAGACTAAT 180 7GGGAAGCGG GTAGGCTCCA GGGAGTGGCT CTCAGAGAGC AGACCATTTA CTGAGCTC 238 (2) INFORMATION FOR SEQ ID NO: 19: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: lo2 base pairs (B) TYPE: nucleic acid SUBSTITUTE SHEET (RULE 26) WO 96/02640 PCT/GB95/01651 51 (C) STRANDEDf-iESS : COuble (D) TOPOLOGY: linear (ii) MOLECULE TYPE: cDNA (xi) SEQUENCE DESCRIPTION': SEQ ID NO: 19: AATACAGAGT TTTGTTCTCT ACTCTTATCC TGCTTTCTCC TCCCTCCTAC TTTTCCCTGA 60 CACCTATCTT GTTGTGAAGA CAGGAATTGC ATTAGATAAA ATCAAATCTT TTTTATTTTT 120 TTTTGAGATG GAATCTTGCT CTGTTTCCAG GCTGGAGTGC TG 162 (2) INFORMATION FOR SEQ ID NO: 20: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 472 bass pairs (3) TYPE: nucleic acid (C) STRANDEDNESS: double (D) TOPOLOGY: linear (ii) MOLECULE TYPE: cDNA (xi) SEQUENCE DESCRIPTION: SEQ ID NO: 20: ATCTGGTCAG CAGTGAAGCT CAGTGTACAC ATTCATTCCT TCCTTCACTG CTTGATTTGT 60 CACCAAGTGG TTATTGAGGA TATGCTGTTT GCTAGGTACT ACTTTACTTA TTTATTTGTT 120 TATTTAGAGA TGGGGTCTCA CAATGTTGCC CAG7CTACAG GACAGTGGCT ATTCACAGGT 180 GTGAGCACAG CACACTACAG CCTCAAACTC CTGAGTTCAA GAGATCCTCC TGCCTCAGTC 240 TCTCGAGTAG CTGGGACTAC AGGGATGTGC CACCACACAT GGCTTAGGCT CTACTTTAGC 300 TGCTACTTGA AGGATGAAGA TAGGAGGAGA CACTCTTATT TTATTTGATT TCTTTTTTTT 360 TTTTTTTTTT TTGACAGAGT TTTGCTCTGT TGCCAGGCTG GAGTGCTCAC TGCAACCTCC 420 ACCTCCAGGT CAAGCAATTC TCCTGCTCAG CCTCCGAG7A GTCGGACCAA GG 47 2 (2) INFORMATION FOR SEQ ID NO: 21: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 2119 base pairs (3) TYPE: nucleic acid (C) STRANDEDNESS: double (D) TOPOLOGY: linear SUBSTITUTE SHEET {RULE 26)' WO 96/02640 PCT/GB95/01651 52 (ii) MOIECULE TY?Z: cDNA (xi) SEQUENCE DESCRIPTION: SI GGAATTCCCA TTCCTGTCCT GTACCCTTGC AGTGGCTCCA CTTCTGTTGT GTTTCTGAAC CATCCCTTCT GGCACACCAA GATCCTCCAC GGTTATCCAT GGTACAGAAG ACAGGATTTA CATGTAGGAG ATAACGATAT GGAAGACCTT GATAAATGTT CCCTGAAACA TAAGAAACAG TTGGGAGGGC CGAGGCCAGG CAGGCAAATT GCCAACATGC AGAAACTCCG TCTCTACTAA CGTGCCTGTA GTCCCAGCTA CTCGGGAGGC GCAGAGGTTG CAGTGAGCCA AGATCGCGCC ACTTGGTCAA AAAAAAAAAA AAAAAAAAAA GAGATGAGGA CAAAGAAGAC GAATCGGTGG TGACATGAAG CTTCATGCCA GCAAATTAAA TACTTGCTCA GGGGCACTGA CCTTATAGAG TCCAATCTTT CCACTGGCTT GGTCCTTCCC CAAGTTATTG GTCTTAGATT TATGTAATGT CGGTAGGAGT GGTTAGGGGT GGGGAATCTG TTTTTTTTTT TTTTTTTTAA AGATAGGGTC GTGCAGTGGA GTGAACATGG CTCACTGCAG TGCCTCAGCC CCTCAAGTAG CTGGGACTAC TTTTGTAGAG ATGGGATTTT ACCATGTTGC TGATCCACCA GACTCGGCCT CCCAAAATGC GCCTAGATGC TTTCATACAG GCTTTTCAAT GATCCAAGTT ATATCGGATT GTTGTAGTCT Q ID NO: 21: AGTGCCTCTG GGTGGAATGC CGACAAATGG 60 ATGTATCTCT TGCTATCAGA ACTTTCTGCT 120 ATTCCCTTCA CTCATGCCAC TTCATATACT 180 ACTGAGAGGA CTTTTCCCTG ACTCTGAATA 240 CAGTATGTAA GTCTTAAATA GATTGGTTGG 300 CGCAGCGGCT CCTGTCTGTA ATCTAGCACT 3 60 GCCTGAGCTC AGAAGTTTGA GACCAGCCTG 4 20 AAATACATAA ATTAACCGGG CATGGTAACA 480 TGAGGCAGGA GAA7CACTTG AGCCTGGGAG 540 ACTGCATTCC AGCCTGGCCA ACAGAGTGAG 600 AAAAGGAAGA AGAAGAAGAA ATCAGGTTTA 660 CATGAAGGAG CTAAGAGCTA CTTGTCACCA 720 GGAGCTATTC AGAACTAGTA TCCTCAACTC 780 ATTCCAGACA TAAGCTTGTT CAGCCTTAAG 840 ACTTTCTGTG GCCAACTCTG AGGTTGTCTA 900 CTCAATGCCA GTGTAGTATT TGGTTATTTA 960 ATAATAGCTC GTAGGATAGC TAGATTCTTT 1020 TCACTTTGTC TCCCAGGATG GATGGATGGA 1080 CCTCGACCTC CTGTGCTCAA G7GTTCCTCC 1140 AGGCACATGT CACCATGCCC AGCTAATTTT 1200 CCAGGCTGGT CTCGAGCTCC TGGGCTCAAG 1260 CGGGATTACA GGTGTGAGCC ACTGTGCCTG 1320 TATGCATTTT CCTTAAGTAG GAAGTCTTAA 1380 ACGTTCCCAT ATTCTATTCC TATTTCTGAG 1440 SUBSTITUTE SHEET (RULE 26) CC7TCAC7CA i GG _ . GGACrt C7CCACAT7C A7777C7GA7 CnC.-^GnC.nC i GGGAAGCAGG GATACTGGGA CG77TCTGTC CCAGAGCCCC TTCAGGTTCT C7G77CCC7G GACATAGA7G 7GAGC . AC-.-. —---vvj AG7GCCAGC7 C7GA7CC7GG TGCATGTC7C 7AGG«jGGGAA TGCCTCAC77 C77A7A7TGC GC77CCCAGA ACCAACCC7A ATCA7GG • ii A/*iC - - . XC GAGGGAAACG AAAAG7AGGG TTGGCATGAC CAGTC7C7C7 TGAGGCTT7C 7GCATGAA7A TGGGGG7AGC CAAAA7GAGG CCA7CCTGGC ~AAGC.---.77C G77A7GGAG 53 C 4 AA» ,C.uw GAC7CTGGCA GCGGGAAGCT CCCCATGCCC C A A G A A A C A A TGG CC.-aG.-.O P1. 7GAA7TATGG 7CAT7C7C77 TAAATAAATG TTC7TTGTCC ACAA.-.A7G7G GCC77G77AC 7G7GATGACA CGGTATACAA 77CTTTCTTC AGGGCTAAAC ACAATACCTG AAGGAAGCTG CC7AGATGTA AAACTGAGTG CTCTGT7CCT - vj — GG A7 TACACCCCC7 CCTT7ATTGT CTCAAG7AAC AAACCCAAA7 C « ATGGAC7A GCAGGCTCAG GGCC7TGGTA ATGCTTCCAT C-GTGGGCA7C GC7GC7GAAA 1500 1560 1620 1680. 1740 1800 1860 1920 1980 2040 2100 SUBSTITUTE SHEET (RULE 26) 54 INDICATIONS RELATING TO A DEPOSITED MICROORGANISM (PCTRule 13 bis) A. The indications made below relate to the microorganism referred to in the description 9 , line 13-15 on page B. IDENTIFICATION OF DEPOSIT Further deposits are identified on an additional sheet | | Name of depositary institution NATIONAL COLLECTIONS OF INDUSTRIAL AND MARINE BACTERIA LTD Address of depositary institution (includingpostal code and country) 23 ST MACHAR DRIVE ABERDEEN AB2 1RY SCOTLAND -UNITED KINGDOM Date of deposit FEBRUARY 1995 Accession Number NCIMB 40709 C. ADDITIONAL INDICATIONS (leave blank if not applicable) This information is continued on an additional sheet | | ESCHERICHIA COLI DH5 <*. F' (K12) CONTAINING PLASMID pHA-2 D. DESIGNATED STATES FOR WHICH INDICATIONS AREMADE (if the indications ore not for all designated States) ALL STATES E. SEPARATE FURNISHING OF INDICATIONS (leave blank if not applicable) The indications listed below will be submined to the International Bureau later (specify the general nature of the indications e.g., 'Accession Number of Deposit') ACCESSION NO DATE OF DEPOSIT CONSTRUCT DEPOSITED 40709 FEBRUARY 1995 pHA-2 For receiving Office use only This sheet was received with the international application 111 SEPTEMBER 1995 Authorized officer D. J. MACKERNESS (MRS! For International Bureau use only [""I Tb's sheet was received by the International Bureau on: Authorized officer Form PCT/RO/134 (July 1992) 55 P20170NZ ifi-

Claims (16)

CLAIMS £ o o; i

1. A recombinant DNA construct comprising, in the 5' to 3' direction and operatively linked: (a) the 5' flanking sequence of SEQ ID NO 21; (b) a DNA sequence encoding (1) a signal sequence and (2) a-lactalbumin or a functional equivalent thereof; and (c) the 3' flanking sequence of any one of SEQ ID NO'S 16 to 20; the DNA construct being adapted to express the a-lactalbumin or functional equivalent thereof in a non-human transgenic animal.

2. A recombinant DNA construct comprising, in the 5' to 3' direction and operatively linked: (a) at least about 1.8 kb of 5'-flanking sequence from the human a-lactalbumin gene including the a-lactalbumin promoter; (b) a DNA sequence encoding (1) a signal sequence; and (2) a-lactalbumin or a functional equivalent thereof; (c) at least about 3 kb of 3'-flanking sequence from the human a-lactalbumin gene - 56 the DNA construct being adapted to express the a-lactalbumin or functional equivalent thereof in a non-human transgenic animal.

A recombinant DNA construct as claimed in claim 1 or 2 comprising about 3.7 kb of 5' flanking sequence and about 13 kb of 3' flanking sequence.

A recombinant DNA construct as claimed in claim 1, 2 or 3, wherein the a-lactalbumin is human a-lactalbumin.

A recombinant DNA construct as claimed in any one of claims 1 to 4, wherein the functional equivalent of a-lactalbumin is an a-lactalbumin mutein incorporating amino acid substitutions as compared to wild type a-lactalbumin.

The recombinant DNA construct pHA-1 as described herein.

The recombinant DNA construct pHA-2 as described herein. •?

A vector containing a recombinant DNA construct as claimed in any one of claims 1 to 7.

A host cell containing a vector as claimed in claim 8.

A transgenic animal having a recombinant DNA construct as claimed in any one of claims 1 to 7 integrated into its genome.

A transgenic animal as claimed in claim 10 which is capable of transmitting the construct to its progeny. ~ t yp n 57 QP20.170NZ /y i~

12. A transgenic animal as claimed in claim 10 or 11 which is a lactating female.

13. Transgenic cattle as claimed in claim 10, 11 or 12. 5

14. A method of producing milk having an enhanced content of a-lactalbumin, the method comprising extracting milk from a lactating female transgenic animal as claimed in claim 12. 10

15. Milk produced by a method as claimed in claim 14.

16. a-lactalbumin extracted from milk as claimed in claim 15. END OF CLAIMS