ENDOTHELIAL LINEAGE SPECIFIC TRANSCRIPTIONAL REGULATORY ELEMENT FROM TEK

Abstract: The present invention therefore provides a transcriptional regulatory element which is capable of directing expression of a gene specifically in cells of the endothelial lineage. Preferably, the transcriptional regulatory element comprises the initiation codon and the untranslated sequences of tek, a protein tyrosine kinase expressed during murine cardiogenesis and homologues thereof including the human tek gene. The transcriptional regulatory element may be used to target expression of a gene in cells of the endothelial lineage.

Description: ENDOTHELIAL LINEAGE SPECIFIC TRANSCRIPTIONAL REGULATORY ELEMENT FROM TEK FIELD OF THE INVENTION The invention relates to a novel transcriptional regulatory element which is capable of directing expression of a gene specifically in cells of the endothelial lineage; a recombinant molecule containing the transcriptional regulatory element; a transformant host cell including the recombinant molecule; a DNA construct comprising the transcriptional regulatory element operatively linked to a gene and a reporter gene; and, the use of the transcriptional regulatory element to target expression of a gene in cells of the endothelial lineage. BACKGROUND OF THE INVENTION Tissue specific transcriptional regulatory elements have been identified which have been used to target expression of exogenous genes in cells and in transgenic animals. For example, DNA constructs using an erythroid specific transcriptional element and an oncogene encoding a protein having protein-tyrosine kinase (PTK) activity have been used to produce transgenic animals which have cardiovascular disease (Yee, S.P. et al. (1989) P.N.A.S., U.S.A. 86, 5873-5877). The ability to introduce into animals exogenous genes which are selectively expressed in a particular cell type provides wide ranging experimental as well as practical opportunities. In particular it permits investigation of the role of a substance in the development, determination, migration, or proliferation of cells of a particular lineage. SUMMARY OF THE INVENTION The present inventors have identified a transcriptional regulatory element characterized by endothelial specific expression. The element is expressed in cells of the endothelial lineage including mature and progenitor cells. This is the first report of a transcriptional regulatory element which is capable of directing expression specifically in cells of the endothelial lineage. The present invention therefore provides a transcriptional regulatory element which is capable of directing expression of a gene specifically in cells of the endothelial lineage. Preferably, the transcriptional regulatory element comprises the initiation codon and the untranslated sequences of tek, a protein tyrosine kinase expressed during murine cardiogenesis and homologues thereof including the human tek gene. Most preferably, the transcriptional regulatory element is a 7.2 kb fragment extending from the Bgl II site to the Kpn I site as shown in Figure 3. The invention further provides a method of preparing the transcriptional regulatory element. The transcriptional regulatory element may be constructed by synthesis and ligation of DNA oligomers. The element may also be isolated by selectively amplifying the region of the transcriptional regulatory element using the polymerase chain reaction method and genomic DNA. The invention also permits the construction of nucleotide probes which are unique to the transcriptional regulatory element of the invention. Thus, the invention also relates to a probe comprising a nucleotide sequence substantially homologous to the transcriptional regulatory element of the invention. The probe may be labelled, for example, with a radioactive substance and it may be used to select from a mixture of nucleotide sequences a transcriptional regulatory element of the invention or an element homologous thereto. The invention also relates to a recombinant molecule adapted for transformation of a host cell comprising a transcriptional regulatory element of the invention and a gene operatively linked to the transcriptional regulatory element. A transformant host cell including a recombinant molecule of the invention is also provided. Still further, this invention provides plasmids which comprise the transcriptional regulatory element of the invention. In an embodiment of the invention a recombinant molecule comprising the transcriptional regulatory element of the invention operatively linked to a gene and a reporter gene is provided. The recombinant molecules of the invention may be used to produce transgenic non-human mammals. Accordingly the invention relates to a method of producing a transgenic non-human mammal characterized as having a plurality of cells containing a recombinant molecule of the invention, or an ancestor of the mammal at an embryonic stage, comprising (a) introducing the recombinant molecule into a pronucleus of a mammalian zygote by microin ection, said zygote being capable of development into a mammal, thereby obtaining_a genetically transformed zygote; (b) transplanting an embryo derived from the genetically transformed zygote into a pseudo- pregnant female capable of bearing the embryo to term and- (c) if desired allowing the embryo to develop to term. The invention further relates to a transgenic non-human mammal all of whose germ cells and somatic cells contain a recombinant molecule of the invention introduced into the mammal, or an ancestor of the mammal at an embryonic stage. Still further the invention relates to cell cultures of cells of the transgenic mammals. The invention also relates to a method of determining the affect of a substance on cells of the endothelial lineage comprising producing a transgenic non- human mammal characterized as having a plurality of cells containing a recombinant molecule comprising the transcriptional regulatory element of the invention operatively linked to a gene encoding the substance, or an ancestor of the mammal at an embryonic stage, comprising (a) introducing the recombinant molecule into a pronucleus of a mammalian zygote by microinjection, said zygote being capable of development into a mammal, thereby obtaining a genetically transformed zygote; (b) transplanting an embryo derived from the genetically transformed zygote into a pseudo-pregnant female capable of bearing the embryo to term and (c) isolating the embryo or allowing the embryo to develop to term, and (d) determining the affect of the substance on cells of the endothelial lineage by comparison to a control. In an embodiment of the invention, a method of determining the affect of a substance on cells of the endothelial lineage is provided comprising producing a transgenic non-human mammal characterized as having a plurality of cells containing a recombinant molecule comprising the transcriptional regulatory element of the invention operatively linked to a gene and a reporter gene encoding a phenotype which is not displayed by the mammal, or an ancestor of the mammal at an embryonic stage, comprising (a) introducing the recombinant molecule into a pronucleus of a mammalian zygote by microinjection, said zygote being capable of development into a mammal, thereby obtaining a genetically transformed zygote; (b) transplanting an embryo derived from the genetically transformed zygote into a pseudo-pregnant female capable of bearing the embryo to term and (c) isolating the embryo or allowing the embryo to develop to term, (d) assaying for the phenotype of the reporter gene in the embryo or transgenic non-human mammal to determine the pattern and extent of expression of the gene, and (e) determining the affect of the substance on cells of the endothelial lineage by comparison to a control. DESCRIPTION OF THE DRAWINGS The invention will be better understood with reference to the drawings in which: Figure 1 shows the nucleotide and deduced amino acid sequence of tek; Figure 2 shows the nucleotide and deduced amino sequence of a 1601 bp DNA segment of tek; Figure 3 is a restriction map showing the transcriptional regulatory element of the invention fused to reporter gene LacZ; Figure 4 is a schematic diagram showing the predicted structure of tek; Figure 5 shows a Northern blot hybridization analysis of expression of tek in 12.5 day murine embryonic heart; Figure 6 shows the in situ hybridization analysis of expression of tek in the 12.5 day embryo; Figure 7 shows the expression of tek precedes that of von Willebrand factor in 8.5 day embryos; Figure 8 shows expression of tek in whole mount embryos(A., B., and C); expression in Day 8.0 embryos (D.); mRNA distribution in a Day 9.5 embryo (E.); and En2 expression in a Day 8 embryo (F.); Figure 9 shows the expression of tek precedes that of von Willebrand factor in the developing leptomeninges and in particular the absence of immunohistochemical staining of von Willebrand factor in Day 12.5 leptomeninges (A); in situ detection of tek expression in Day 12.5 leptomeninges(B); staining of von Willebrand factor in Day 14.5 leptomeninges (C); Figure 10 shows the expression of tek in adult vasculature and in particular bright field illumination of a section through the upper heart region of a 3 week-old mouse hybridized with an [ 35 S]-labelled tek probe (B); bright field illumination showing tek expression in endothelial cells lining the artery and vein respectively (C); Figure 11 shows the partial nucleotide sequence of the transcriptional regulatory element of the invention; Figure 12 shows expression of LacZ in Day 8.5 embryos produced using a DNA construct comprising the transcriptional regulatory element of the invention and LacZ; and Figure 13 shows tek mRNA distribution in a Day 8.5 embryo; Figure 14 shows a comparison of a portion of the deduced amino acid sequence of the novel receptor tyrosine kinase protein of the invention with that of other tyrosine kinases. DETAILED DESCRIPTION OF THE INVENTION Copending application Serial No. 07/921,795 relates to a novel protein tyrosine kinase expressed during murine cardiogenesis which is designated tek. The human homolog of tek has been recently reported by Ziegler, G. F. et al., Oncogene 8:663-670, (1993). The tek locus was mapped to chromosome 4, between the brown and pmv-23 loci. This region is syntenic with human chromosomal regions lp22-32, 9q31-33, and 9p22-13. The deduced amino acid sequence of tek predicts that it encodes a putative receptor tyrosine kinase that contains a 21 amino acid kinase insert and which is most closely related in its.catalytic domain to FGFR1 (mouse fibroblast growth factor) and the product of the ret proto-oncogene. Figure 1 shows the nucleotide and deduced amino acid sequence of tek. The present inventors have also identified the initiation site of translation of tek. In the adult and all stages of embryonic development examined, tek expression was found to be restricted to cells of the endothelial lineage. Specifically, in situ hybridization analysis of adult tissues, as well as sectioned and whole mount embryos, showed that tek is specifically expressed in the endocardium, the leptomeninges and the endothelial lining of the vasculature from the earliest stages of their development. Moreover, examination of the morphology of teJc-expressing cells, and staging of tek expression relative to that of the endothelial cell marker von Willebrand factor, revealed that tek is expressed prior to von Willebrand factor and appears to mark the embryonic progenitors of mature endothelial cells. The present inventors have identified a transcriptional regulatory element located upstream of tek which specifically directs expression of a gene in cells of the endothelial lineage. The transcriptional regulatory element has been found to direct expression in both mature and progenitor endothelial cells. In particular, the present inventors isolated a DNA segment from a mouse genomic bacteriophage library using a 5'-prime probe which contained the initiation codon and untranslated sequences of tek using the procedures of Sambrook et al., 1989, Molecular Cloning, A Laboratory Manual. Cold Spring Harbour Lab. Press. A 16 kb phage clone was shown by hybridization and sequence analysis to contain a single exon with 175 bp homologous to the cDNA. A DNA fragment extending from the " Bgl II restriction site located at nucleotide 110 of the cDNA to the nearest Kpn I in the phage was cloned upstream of the bacterial gene lacZ (see Figure 3). This reporter construct containing 7.2 kb of the tek gene was microinjected into pronuclei of fertilized randomly bred CD-I mice using procedures as set out in Hogan et al. (1986, Manipulating the Mouse Embryo, A Laboratory Manual. Cold Spring Harbor Lab. Press). Three transgenic founder embryos were dissected from their foster mothers and yolk sac DNA analyzed for the presence of the transgene. Expression of the transgene was determined by the X-gal staining of whole embryos and subsequent sectioning of the embryos. The 7.2 kb fragment was able to drive lacZ expression in endothelial cells that had previously been shown to express tek RNA thus demonstrating that this DNA contained the tek transcriptional regulatory element. The partial nucleotide sequence of the transcriptional regulatory element is shown in Figure 11. The invention further provides a method of preparing the transcriptional regulatory element. The transcriptional regulatory element may be isolated by selectively amplifying the region of the transcriptional regulatory element using the polymerase chain reaction method and genomic DNA. It is possible to design synthetic oligonucleotide primers from the sequence shown in Figure 11 for use in PCR and for screening genomic libraries, in particular human genomic libraries. An amplified fragment can be cloned and characterized by DNA sequence analysis. The nucleotide sequence of the transcriptional regulatory element will also permit the element to be constructed by synthesis and ligation of DNA oligomers. The transcriptional regulatory element may be proven functional by assessing the transient expression of a construct bearing a reporter gene. For example, using the reporter gene for B-galactosidase (LacZ) or chloramphenicol acetyltransferase (CAT) after transfeetion of the DNA into host cells. It will be appreciated that the invention includes nucleotide sequences which have substantial sequence homology with the nucleotide sequence of the transcriptional regulatory element of the invention. The term "sequences having substantial sequence homology" means those sequences which have slight or inconsequential sequence variations i.e. the homologous sequences function in substantially the same manner to produce substantially the same result as the actual sequence. The variations may be attributable to local mutations or structural modifications. The invention also permits the construction of nucleotide probes which are unique to the transcriptional regulatory element of the invention. Thus, the invention also relates to a probe comprising a nucleotide sequence substantially homologous to the transcriptional regulatory element of the invention. The probe may be labelled and it may be used to select from a mixture of nucleotide sequences a transcriptional regulatory element of the invention or an element substantially homologous thereto. A nucleotide probe may be labelled with a radioactive label which provides for an adequate signal and has sufficient half-life such as 32 P, Η, C or the like. Other labels which may be used include antigens that are recognized by a specific labelled antibody, fluorescent compounds, enzymes, antibodies specific for a labelled antigen, and chemiluminescent substances. An appropriate label may be selected having regard to the rate of hybridization and binding of the probe to the nucleotide to be detected and the amount of nucleotide available for hybridization. The invention also relates to a recombinant molecule adapted for transformation of a host cell comprising a transcriptional regulatory element of the invention and a gene operatively linked thereto. The transcriptional regulatory element of the invention operatively linked to a gene may be incorporated in a known manner into a recombinant molecule which ensures good expression of the protein encoded by the gene. The transcriptional regulatory element of the invention may be incorporated into a plasmid vector, for example, a retroviral vector, pECE. The transcriptional regulatory element of the invention may be operatively linked to a reporter gene or a gene encoding a substance which has toxic or therapeutic activity including a factor which modulates angiogenesis. Examples of reporter genes, factors which modulate angiogenesis, and substances with toxic or therapeutic activity are discussed below. A transformant host cell including a recombinant molecule of the invention and a cell line containing such transformant host cells is also provided. Examples of suitable host cells include human endothelial cells such as umbilical vein endothelial cells and rabbit aortic endothelial cells. The invention also relates to a recombinant molecule comprising a transcriptional regulatory element of the invention operatively linked to a gene and a reporter gene. The reporter gene may be introduced into the recombinant molecule using conventional methods such as those described in Sambrook et al., 1989, Molecular Cloning, A Laboratory Manual. Cold Spring Harbour Lab. Press. The recombinant molecule may also be synthetically produced using conventional methods. Further, the recombinant molecule may be introduced into a host cell using conventional methods. The reporter gene should be under the control of the transcriptional regulatory element and the pattern and extent of expression of the gene operatively linked to the transcriptional regulatory element may accordingly be determined in cells of the endothelial lineage. Preferably the reporter gene codes for a phenotype not displayed by the host cell and the phenotype may be assayed quantitatively. Examples of suitable reporter genes include lacZ (B-galactosidase), neo (neomycin phosphotransferase) , cat ( chloramphenicol acetyltransferase) dhfr (dihydrofolate reductase), aphlV (hygromycin phosphotransferase), lux (luciferase), uidA (B-glucuronidase) . Preferably, the reporter gene is lacZ which codes for B-galactosidase. B-galactosidase may be assayed using the lactose analogue X-gal(5-bromo-4-chloro- 3-indolyl-b-D-galactopyranoside) which is broken down by B-galactosidase to a product that is blue in color. (See for example Old R.W. & Primrose S.B., Principles of Gene Manipulation An Introduction to Genetic Engineering, 4th ed. Oxford University Press at pages 63-66 for a discussion of procedures for screening for recombinants) . The recombinant DNA of the invention may be used to produce transgenic non-human mammals. Accordingly the invention relates to a method of producing a transgenic non-human mammal characterized as having a plurality of cells containing a recombinant molecule of the invention, or an ancestor of the mammal at an embryonic stage, comprising (a) introducing the recombinant molecule into a pronucleus of a mammalian zygote by microinjection, said zygote being capable of development into a mammal, thereby obtaining a genetically transformed zygote; (b) transplanting an embryo derived from the genetically transformed zygote into a pseudo- pregnant female capable of bearing the embryo to term and (c) if desired, allowing the embryo to develop to term. The invention further relates to a transgenic non-human mammal all of whose germ cells and somatic cells contain a recombinant molecule of the invention introduced into the animal, or an ancestor of the mammal at an embryonic stage. In a preferred embodiment, plas ids containing recombinant molecules of the invention (for example see Figure 3) are microinjected into mouse embryos. In particular, the plasmids are injected into the male pronuclei of fertilized one-cell mouse eggs; the injected eggs are transferred to pseudo-pregnant foster females; and, the eggs in the foster females are allowed to develop to term. (Hogan, B. et al, (1986) A Laboratory Manual, Cold Spring Harbor, New York, Cold Spring Harbor Laboratory) . It will be realized that methods other than microinjection can be used to generate the transgenic mammals. For instance, retrovirus infection techniques (R. Jaenisch, PNAS U.S.A. 73, p. 1260 (1976); Cell 12, P. 691 (1977); H. Varmus, in RNA Tumor Viruses, R. Weiss et al, Cold Spring Harbor Laboratory, Cold Spring Harbor, NY, (1982) p. 369-512; D. Jahner and R. Scienisch, Nature 287, p. 456 (1980) and R. Jaenisch et al, Cell 24, p. 519 (1981)), direct introduction of DNA into sperm cells followed by in vitro fertilization (Lavitrano, M., et al, Cell. 57, p. 717), and techniques involving the introduction of DNA by viral transduction or transfection into embryonic stem cells which are able to contribute to the germ line when injected into host blastocysts can be employed (A. Bradley et al, Nature 309, p. 255 (1984); A. Gossler et al, PNAS U.S.A. 83, p. 9065 (1986)). Although experimental animals used in the preferred embodiment disclosed were mice, the invention should not be limited thereto. It may be desirable to use other species such as rats, hamsters and rabbits. The invention also relates to a method of determining the affect of a substance on cells of the endothelial lineage comprising producing a transgenic non- human mammal characterized as having a plurality of cells containing a recombinant molecule comprising the transcriptional regulatory element of the invention operatively linked to a gene, or an ancestor of the mammal at an embryonic stage, comprising (a) introducing the recombinant molecule into a pronucleus of a mammalian zygote by microinjection, said zygote being capable of development into a mammal, thereby obtaining a genetically transformed zygote; (b) transplanting an embryo-derived from the genetically transformed zygote into a pseudo- pregnant female capable of bearing the embryo to term and (c) isolating the embryo or allowing the embryo to develop to term, and (d) determining the affect of the substance on cells of the endothelial lineage by comparison to a control. In an embodiment of the invention a method of determining the affect of a substance on cells of the endothelial lineage is provided comprising producing a transgenic non-human mammal characterized as having a plurality of cells containing a recombinant molecule comprising a transcriptional regulatory element of the invention linked to a gene encoding the substance, and a reporter gene encoding a phenotype which is not displayed by the mammal, or an ancestor of the mammal at an embryonic stage, comprising (a) introducing the recombinant molecule into a pronucleus of a mammalian zygote by microinjection, said zygote being capable of development into a mammal, thereby obtaining a genetically transformed zygote; (b) transplanting an embryo derived from the genetically transformed zygote into a pseudo- pregnant female capable of bearing the embryo to term and (c) if desired, allowing the embryo to develop to term, (d) assaying for the phenotype of the reporter gene in the embiyo or transgenic mammal to determine the pattern and extent of expression of the gene, and (e) determining the affect of the substance on cells of the endothelial lineage by comparison to a standard. As discussed above, the reporter gene should be under the control of the transcriptional regulatory element and accordingly the pattern and extent of expression of a gene operatively linked to the transcriptional regulatory element may be determined by assaying for the phenotype of the reporter gene. Preferably the reporter gene codes for a phenotype not displayed by the host cell and the phenotype may be assayed quantitatively. Examples of suitable reporter genes include lacZ (β-galactosidase), neo (neomycin phophotransferase ) , cat (chloramphenicol acetyltransferase) dhfr (dihydrofolate reductase), aphlV (hygromycin phosphotransferase), lux (luciferase) , uidA (β-glucuronidase) . Preferably, the reporter gene is lacZ which codes for β-galactosidase. β-galactosidase may be assayed using the lactose analogue X-gal(5-bromo-4-chloro- 3-indolyl-β-D-galactopyranoside) which is broken down by β-galactosidase to a product that is blue in color. (See for example Old R.W. & Primrose S.B., Principles of Gene Manipulation An Introduction to Genetic Engineering, 4th ed. Oxford University Press at pages 63-66 for a discussion of procedures for screening for recombinants) . Cells of the transgenic mammals of the invention and produced by the methods of the invention may be cultured using standard tissue culture techniques. The present invention allows the manipulation of endothelial cell physiology by targeting expression of a substance in cells of the endothelial lineage in a mammal. The above described methods, transgenic animals and cell cultures derived therefrom, can therefore be used to assess the role of a substance in the determination, migration, or proliferation of cells of the endothelial lineage. In particular, the invention provides a mechanism for investigating vascularization of tumors and the control of angiogenesis. A transgenic mammal may be produced which expresses a substance exclusively in cells of the endothelial lineage. A comparison of endothelial phenotype, morphology, and function using for example immunohistochemical techniques and assays for LDL receptors, and of the pattern and extent of expression of the substance in the animal with a control transgenic animal will provide an indication of the affect of the substance on cells of the endothelial lineage. Substances which may modulate the angiogenic process (herein also referred to as angiogenic factors) may be tested using the above described method. Examples of such substances include substances derived from human and animal tissues which stimulate the proliferation or migration of normally quiescent endothelial cells in culture or promote neovascularization in vivo including factors which are associated with the vascularization that permits tumor growth; substances which are inhibitors of angiogenesis such as transforming growth factor β, tumor necrosis factor α, human platelet factor 4 (PF4) and α interferon; substances which suppress cell migration, such as proteinase inhibitors which inhibit proteases which may be necessary for penetration of the basement membrane, in particular, tissue inhibitors of metalloproteinase TIMP-1 and TIMP-2; and other proteins such as protamine which has demonstrated angiostatic properties. For a review of factors which play a role in angiogenesis see Maione T.E. and R.J. Sharpe, TIPS, November 1990 Vol. 11 page 457. The transcriptional regulatory element of the invention may be used in gene therapy to introduce a foreign gene into endothelial cells to correct or prevent vascular disorders. (See Nabel et al., JACC Vol 17, No.6, page 189B, 1991 for a discussion of gene transfer into vascular cells) . For example, the transcriptional regulatory element of the invention may be used to express foreign genes at specific sites in the circulation. Endothelial cells are found at diseased sites and accordingly, the transcriptional regulatory element of the invention may be used to target therapeutic agents including anticoagulants, vasodilator, and angiogenic factors (see above discussion) to endothelial cells found at diseased sites. Thus, genetic modification of endothelial cells utilizing the transcriptional regulatory element of the invention may be used in the treatment of acquired vascular disorders such as hypertension, atherosclerosis restenosis, arthritis and cancer. Endothelial cells line all blood vessels and accordingly the transcriptional regulatory element of the invention may be used to target therapeutic agents into the bloodstream. Thus, genetic modification of endothelial cells utilizing the transcriptional regulatory element of the invention may also be used in the treatment of systemic or inherited disorders. For example, the transcriptional regulatory element of the invention could be operatively linked to the factor VIII gene and introduced into a population of endothelial cells to correct a hemophilia disorder. Endothelial cells genetically modified in vitro using the transcriptional regulatory element of the invention i.e transformant host cells or cell lines containing transformant host cells of the invention, may be used to deliver gene products to the vasculature. In particular, endothelial cells genetically modified in vitro using the transcriptional regulatory element of the invention may be introduced into the vascular wall by catheterization. Using this method, therapeutic proteins may be introduced into diseased arterial segments. The method may be particularly useful for introducing growth inhibitor proteins into an angioplasty site in patients with restenosis who have undergone coronary angioplasty. Endothelial cells genetically modified in vitro using the transcriptional regulatory element of the invention may be used to improve the performance of prosthetic vascular grafts. Prosthetic vascular grafts may be seeded with endothelial cells genetically modified using the transcriptional regulatory element of the invention, to produce therapeutic proteins which may prevent thrombosis or promote repopulation. Vascular stents may also be populated with genetically modified endothelial cells to reduce problems such as thrombosis. A gene under the control of the transcriptional regulatory element of the invention i.e recombinant molecules of the invention, may be directly introduced into endothelial cells in vivo using delivery vehicles such as retroviral vectors, adenoviral vectors and DNA virus vectors. They may also be introduced into endothelial cells in vivo using physical techniques such as microinjection and electroporation or chemical methods such as coprecipitation and incorporation of DNA into liposomes. The invention will be more fully understood by reference to the following examples. However, these examples are merely intended to illustrate embodiments of the invention and are not to be construed to limit the scope of the invention. EXAMPLES The following materials and methods were utilized in the investigations outlined in the examples: DNAs AKR/J, DBA, and AKR/J X DBA recombinant inbred mouse DNAs were obtained from Jackson Labs (Bar Harbor, Maine), digested with Accl, blotted to Zeta-Probe nylon membrane (Bio-Rad), and probed with the 1.6 kb tek cDNA labelled by random priming (Feinberg, A.P. & Vogelstein, B. (1983) Analyt . Biochem. , 132, 6-13). Hybridization was performed overnight at 65 * in 200 mM sodium phosphate pH7.0, 7% sodium dodecyl sulfate (SDS), 1% bovine serum albumin (BSA), and 1 mM EDTA. Filters were washed twice at 55 * in 2 x SSC (1 x SSC= 0.15 M NaCl, 0.015 M sodium citrate pH7.0) and 0.1% SDS and twice in 0.2 x SSC and 0.1% SDS, and exposed overnight to Kodak XAR-5 film. Mice Embryos and adult mouse tissues were obtained from random bred CD-I stocks (Charles River, Quebec). Embryos were staged as Day 0.5 on the morning of a vaginal _ plug. RNA purification and analysis Total RNA was extracted from pools of 30 to 40 Day 9.5 and 12.5 murine embryonic hearts with RNAzol (CINNA/BIOTECX Lab. Int.), with some added modifications. Briefly, tissues were washed with ice cold phosphate buffered saline (PBS) and homogenized in 2.5 ml of RNAzol. Chloroform (250 μl) was added and the tubes were mixed vigorously and then chilled on ice for 15 min. The suspension was centrifuged for 15 min at 4 * after which the aqueous phase was collected and re-extracted twice more with phenol/chloroform/isoamyl alcohol (25:24:1; vόl:vol:vol) . The RNA was precipitated with an equal volume of isopropanol, collected by centrifugation, and the pellet resuspended in diethylpyrocarbonate (DEPC)- treated 0.4 M sodium acetate, pH5.2. The RNA were then precipitated with two volumes of 95% ethanol, washed with 70% and 95% ethanol, dried, and resuspended in DEPC treated 0.3 M sodium acetate, pH5.2. The RNA concentration was determined and the RNA stored at -70' until use. Poly A - containing RNA was purified from a pool of 100 to 150 Day 12.5 murine embryonic hearts with a QuickPrep mRNA isolation kit (Pharmacia) as outlined by the supplier. For Northern blot hybridization, 5 μg of poly A - containing RNA from 12.5 day embryonic heart was electrophoresed through a formaldehyde-agarose gel and blotted to a Zeta-Probe nylon membrane (Bio-Rad) according to established protocols (Sambrook et al . , 1989, Molecular Cloning. Cold Spring Harbor Laboratory Press). The membrane was hybridized with a [ 32 P]-labelled antisense riboprobe synthesized from the 1.6 kb tek cDNA in run off reactions with SP6 RNA polymerase (Promega) . Reverse Transcription Coupled to the Polymerase Chain Reaction (RT-PCR) First strand cDNA was synthesized in a total reaction volume of 20 μl containing 20 μg of total RNA, 200 units of Mo-MLV-reverse transcriptase (BRL), either 1 μg of oligo-d(T) 18 (Day 12.5 RNA) (Boerhinger Mannheim) or 2 μg of random hexamer primers (Day 9.5 RNA) (Boerhinger Mannheim), 1 x PCR buffer (Cetus), 2.5 mM MgCl 2 , 1 mM of dNTPs (Pharmacia), 40 units of RNAsin (Promega), and 12.5 mM dithiothreitol. The RNA was heated to 65 * C for 10 min and cooled quickly on ice prior to addition to the reaction components. The reaction was allowed to proceed for 1 h at 37 * and then terminated by heating for 5 min at 95 * . For PCR, the reaction mixture was adjusted to a final volume of 100 μl containing 1 x PCR buffer, 1.5 mM MgCl 2 , 800 μM dNTPs, and 1 μg of each of the two degenerate tyrosine kinase oligonucleotide primers described by Wilks, A.F. (1989) Proc. Natl . Acad. Sci . , 86, 1603-1607. Amplification was performed with a Ericomp thermocycler using the following parameters: denaturation for 2 min at 94 * , annealing for 2 min at 42 * , and extension for 4 min at 63 * . After 40 cycles, the reaction products were collected by ethanol precipitation and electrophoresed through at 2% low-melt agarose (Sea Plaque) gel. In most cases a band of approximately 200 bp was visible within a background smear of ethidium bromide staining. This band was excised and recovered by three cycles of freeze-thaw in 100 μl of water. 10 μl of this solution was then subjected to a second round of PCR under the same conditions described above. Cloninσ and sequencing of RT-PCR products. After the second round of amplification, 10 μl of the reaction mixture were analyzed on a gel for successful amplification. The remaining 90 μl were then ethanol precipitated, digested with EσoRI and BazπHI, gel purified, and ligated to pGEM7Zf+ (Promega) digested with the same enzymes. The ligation mixture was then transformed into MV1190 competent cells, individual ampϊ colonies picked, plasmid DNA prepared, and the cDNA inserts analyzed by single track dideoxynucleotide sequencing (Sanger, F., Nicklen, S. & Coulson, A.R. (1977). Proc. Natl . Acad. Sci . , 74, 5463-5467). A single representative clone of each multiple isolate was sequenced in its entirety. Of the 58 clones analyzed, roughly 10% showed no sequence identity to tyrosine kinases and were disregarded. Isolation of additional tek cDNA sequences. Approximately 10 6 plaques from an amplified, random primed 13.5 day murine embryonic λgtlO cDNA library were hybridized with the 210 bp tek PCR product labelled with [ 32 P]-dCTP by PCR. Hybridization was carried out overnight at 55 * in 50% formamide, 10% dextran sulfate (Pharmacia), 0.5 % BLOTTO, 4 x SSPE (1 x SSPE= 0.18 M NaCl, 10 mM NaH-P0 4 , 1 mM EDTA, pH7.4), 100 μg/ml sheared salmon sperm DNA, and 2 x 10 6 cpm/ml of probe. Filters were washed at 55 * twice in 2 x SSC containing 0.1% SDS and twice in 0.2 x SSC containing 0.1% SDS, dried, and exposed overnight to Kodak XAR-5 film. One clone was isolated from this screen and was found to contain a 1.6 kb cDNA. The sequence of the 1.6 kb cDNA was determined by the method of Sanger et al. (1977) from a set of anchored deletions generated with a standardized kit (Erase - A - Base, Promega). In situ hybridization Embryos isolated on Day 12.5 were dissected away from all extraembryonic tissues whereas embryos at earlier time points were recovered in utero. Embryos and adult tissues were fixed overnight in 4% paraformaldehyde, dehydrated with alcohols and xylenes, and embedded in paraffin. Tissues were sectioned at 6 μm thickness and mounted on 3-aminopropyltriethoxysilane treated slides (Sigma). After removal of paraffin the samples were treated with predigested pronase (Boerhinger Mannheim), acetylated with triethanolamine, dehydrated, and hybridized according to the protocol described by Frohman, N.B., Boyle, M. & Martin, G.R. (1990), Development , 110, 589-607. Dark and bright field photomicroscopy was performed with a Leitz Vario Orthomat 2 photomicroscopic system. Adjacent sections probed with a tek sense probe produced no detectable signal above background. Whole-mount in situ hybridizations were performed using a modification of existing procedures (Tautz, D. & Pfeifle, C. (1989). Chromosoma, 98,81-85;Hemmati-Brivanlou, A., Franck, D., Bolce, M.E., Brown, B.D., Sive, H.L. & Harland, R.M. (1990). Development , 110, 325-330; Conlon and Rossant, in prep.). The hybridization of single-stranded RNA probes labelled with digoxigenin was detected with antidigoxigenin antibodies coupled to alkaline phosphatase. The En2 cDNA was prepared as set forth in Joyner A.L. & Martin, G.R. (1987). Genes and Dev. , 1, 29-38 and expression of En2 is described in Davis, C.A., Holmyard, D.P., Millen, K.J. & Joyner, A.L. (1991) Development, 111:, 287-298. Immunohistochemistry Sections were stained immunohistochemically for von Willebrand factor with a commercially available kit (Biomeda). After color development, slides were counterstained with Harris hematoxylin. EXAMPLE I Isolation and characterization of teJc To identify and characterize tyrosine kinases expressed during murine cardiogenesis, cDNAs were synthesized from 9.5 and 12.5 day embryonic heart RNA by RT-PCR using degenerate oligonucleotide primers previously demonstrated to amplify tyrosine kinase sequences preferentially (Wilks, A.F. 1989, Proc.Satl .Acad. Sci . , 86, 1603-1607). Considerable cellular differentiation and morphogenesis have occurred within the cardiac region of the embryo by Day 9.5. At this stage the heart has developed from the primordial mesoderm cells of the cardiac plate into a primitive bent tube structure, consisting of two endothelial tubes enclosed within the developing myocardium. Between Day 9.5 and 12.5 the heart undergoes additional complex morphological changes in association with the formation of the four chambers and septa characteristic of the adult heart. Sequence analysis of 58 clones obtained following amplification revealed that whereas roughly 10% did not contain sequence similarities to protein kinases the remainder corresponded to 5 distinct cDNAs (Table 1 - Identity and number of tyrosine kinase cDNA clones recovered from Day 9.5 and 12.5 murine embryonic heart by RT-PCR). Four of these cDNAs represented previously characterized tyrosine kinases including, bmk, c-src, c-abl, and the platelet derived growth factor receptor β-subunit (pdgfrb) . The isolation of bmk, c-src, and c-abl is consistent with the broad tissue distribution of these kinases (Wang, J.Y.J. & Baltimore, D. (1983). Mol . Cell .Biol . , 3, 773-779; Ben-Neriah et al . , (1986) . Cell , 44, 577-586; Holtzman, D., Cook, W. & Dunn, A. (1987). Proc.Natl .Acad.Sci . , 84, 8325-8329; Renshaw, M.W., Capozza, M.A. & Wang, J.Y.J. (1988). Mol .Cell .Biol . , 8, 4547-4551). The recovery from embryonic heart of pdgfrb at a relatively high frequency may indicate that pdgfrb plays an important role in cardiogenesis, as has been suggested by recent studies demonstrating that the addition of PDGF-BB to explants of axolotol cardiac field mesoderm stimulates the production of beating bodies (Muslin, A.J. & Williams, L.T. (1991). Development , 112, 1095-1101) the fifth cDNA, which was also isolated at high frequency, was novel and for reasons that will become clear below was designated tek. The 210 bp RT-PCR-derived tek clone was subsequently used to isolate additional tek cDNA sequences. Figure 2 shows the nucleotide sequence of a 1.6 kb tek cDNA isolated from a 13.5 day mouse embryo cDNA library. Translation of this sequence reveals a single large open reading frame that terminates with TAG at nucleotide 907, followed by 696 nucleotides of 3" untranslated sequence. Several features of the deduced amino acid sequence suggest that the 1.6 kb tek cDNA encodes the cytoplasmic portion of a transmembrane RTK, consisting of the catalytic domain followed by a short carboxy-terminal tail of 33 amino acid residues. Figure 14 shows a comparison of the deduced amino acid sequence of tek with that of other tyrosine kinases; Identical sequences are denoted by periods. Dashes were added to allow for optimal alignment. The kinase insert and conserved regions of the catalytic domain are indicated beneath the aligned sequences (Hanks, S.K., Quinn, A.M. & Hunter, T. (1988), Science, 241, 52). Comparative sequences shown are for human Ret (Takahashi, M. & Cooper, G.M. (1987). Mol . Cell .Biol . , 7, 1378-1385), and Jtkl4 (Partanen, J., Makela, T.P., Alitalo, R.,~ Lehv slaiho, H. & Alitalo, K. (1990) Proc.Natl.Acad.Sci. , 87, 8913-8917) and murine Fig (Reid, H.H., Wilks, A.F. & Bernard, 0. (1990) Proc.Natl .Acad.Sci . , 87, 1596-1600). As shown in Figure 14, the putative kinase domain contains several sequence motifs conserved among tyrosine kinases, including the tripeptide motif DFG, which is found in almost all known kinases, and the consensus ATP-binding site motifs GXGXXG followed by AXK 16 amino acid residues downstream (Hanks et al . , 1988). Transmembrane RTK's possess a methionine residue within the motif WMAIESL of conserved region VIII of the catalytic domain (Hanks et al . , 1988) as does tek, and the catalytic domain is interrupted by a putative 21 amino acid kinase insert, a structural motif not found in cytoplasmic tyrosine kinases (Hanks et al . , 1988). Comparison with other tyrosine kinases (Figure 14) reveals that the deduced tek amino acid sequence shows 42% sequence identity to the mouse fibroblast growth factor receptor Fig (Reid et al . , 1990; Safran, A., Avivi, A., Orr-Urtereger, A., Neufeld, G., Lonai, P., Givol, D. & Yarden, Y. (1990). Oncogene, 5, 635-643, Sambrook, J., Fritsch, E.F. & Maniatis, T. (1989). Molecular Cloning. Cold Spring Harbor Laboratory Press) and 45% to the transmembrane RTK encoded by the human c-ret proto- oncogene (Takahashi & Cooper, 1987). In addition, striking sequence identity is observed to a 65 amino acid residue sequence encoded by Jtkl4, a putative tyrosine kinase cDNA isolated from differentiating human K562 cells by RT-PCR (Partanen et al . , 1990). Taken together, the results suggest that tek encodes a novel RTK. EXAMPLE II Chromosomal mapping of the tek locus Mapping of the tek locus was accomplished by monitoring the strain distribution pattern of an Aσcl restriction site polymorphism in recombinant inbred (RI) mouse strains derived from matings between AKR/J (A) and DBA/2J (D) mice. The tek cDNA detects bands of 6.5, 6.1, 1.3 and 6.5, 3.1, 1.3 kb in DNA from the A and D strains, respectively. Southern blot hybridization analysis of DNA from 24 RI mice with the 1.6 kb cDNA probe, and comparison of the segregation pattern with the Jackson Laboratory data base, revealed 95.8% cosegregation between tek and both brown and pmv-23 , two loci that have previously been localized to mouse chromosome 4 (Lyon & Searle, 1989). Table 2 shows the cosegregation of the tek, brown, and pmv-23 loci in A x D strains. In Table 2 for each RI strain, the symbol shown indicates the presence of an allele characteristic of the progenitor from which the strain was derived (A, AKR/J; D, DBA/2J) These data place tek between the brown and pmv-23 loci within 3.8±1.9 centimorgans of each interval. EXAMPLE III Multiple te-c-related transcripts are expressed in embryonic heart tek expression in embryonic heart was examined by Northern blot hybridization using an antisense probe derived from the 1.6 kb tek cDNA. Figure 5 shows a Northern blot hybridization analysis of tek expression in 12.5 day murine embryonic heart; Arrows on the left denote the position of migration of 28 S and 18 S ribosomal RNAs obtained from adjacent lane loaded with total RNA. Figure 5 shows that the tek probe detects 4 transcripts of 4.5, 2.7, 2.2, and 0.8 kb in size in cardiac RNA from 12.5 day mouse embryos. These hybridizing species vary considerably in signal intensity, suggesting that they may differ in relative abundance, with expression of the 2.7 and 2.2 kb transcripts occurring at significantly higher levels than the 4.5 and 0.8 kb RNAs. While the exact relationship among these transcripts is unclear, it is possible that they arise by differential splicing, since the 1.6 kb tek cDNA detects a single genomic locus in mouse DNA by Southern blot hybridization at the same stringency. EXAMPLE IV In situ localization of tek expression during mouse embryogenesis To determine which cell types express tek during development, RNA in situ hybridization analyses were performed on mouse embryos with an antisense riboprobe synthesized from the 1.6 kb tek cDNA. Figure 6 shows the in situ hybridization analysis of tek expression in the 12.5 day embryo; A. Dark field illumination of a para-sagittal section. Bar: 600μm. B. and C. Bright and dark field illumination respectively, of the heart region taken from a mid- sagittal section. Bar: 300 μm. IV and VI, fourth and sixth aortic arches; A, atrium; BA, basilar artery; CV, caudal vein; E, endocardium; L, liver; M, leptomeninges; Ma, mandible; My, myocardium; PC, pericardial cavity; RA, renal artery; SS, sino-auricular septum; SV, sinus venosus; V, ventricle. Figure 6A shows that in 12.5 day mouse embryos, expression of tek is readily detected in the heart, the leptomeninges lining the brain and spinal cord, and the inner lining of major blood vessels, including the caudal vein and basilar and renal arteries. In addition, thin bands of hybridization are observed in the intersomite regions, corresponding to tek expression in the intersegmental vessels. Close examination of the region of the developing heart (Figure 6B and 6C) reveals that te/c is expressed in the endocardium, as well as in cells lining the lumina of the atria, the IV and VI aortic arches, the sinus venosus, and the sino-auricular septum. In addition, tek expression is observed in numerous small blood vessels perforating the liver and mandible. These observations, together with the overall pattern of hybridization seen in the 12.5 day embryo, demonstrate that teJc is expressed in the endothelial cells of the tunica interna , the innermost lining of the blood vessels; hence the designation tunica interna endothelial cell kinase, tele. More detailed information on tek expression was obtained through analysis of sections from earlier developmental stages. Hybridization to 6.5 and 7 day embryos revealed that while tek is expressed strongly in the inner lining of the small blood vessels and capillaries of the maternal decidua, no expression is observed in either the embryo itself or the ectoplacental cone. The absence of tek expression at these stages is consistent with the fact that at 6.5 to 7 days the embryo contains only a small amount of mesoderm from which endothelial cells are known to be derived. Figure 7 shows the expression of tek precedes that of von Willebrand factor in 8.5 day embryos; Adjacent transverse sections through an 8.5 day embryo fixed in utero were either hybridized in situ with an [ 35 S]-labelled tek probe or stained immunohistochemically for von Willebrand factor. A. Bright field illumination of tek expression, Bar: 300 μm. B. Dark field illumination of section in A. C. High magnification of a blood island, slightly out of the field shown in A, depicting silver grains over flat, elongated cells of endothelial-like morphology, Bar: 50 μm. D. Adjacent section to A at higher magnification showing absence of expression of von Willebrand factor in the embryo, Bar: 100 μm. E. Adjacent section to A at higher magnification showing expression of von Willebrand factor in the endothelial lining of the blood vessels of the maternal decidua. Bar: 200 μm. F. High magnification of cephalic region in A showing silver grains over a large, round cell of angioblast-like morphology (arrow). Bar: 50 μm. G. Bright field illumination of a sagittal section of an 8.5 day embryo hybridized in situ with an [ 35 S]-labelled tek probe. Bar: 300 μm. H. Dark field illumination of G. I.- Higher magnification of heart region in A showing silver grains over cells with endothelial- and angioblast-like morphology in the developing endocardium. Bar: 100 μm. J. Higher magnification of somite region in A showing tek- expressing cells extending beneath, and possibly from, the ventral surface of the somites. Bar: 100 μm. A, amnion; Ag, presumptive angioblast; BI, blood island; D, maternal decidua; DA, dorsal aorta; E, endocardium; Ec, ectoplacental cone; En, endothelial cell; G, foregut; HV, head vein; NF, neural fold; S, somite; Y, yolk sac. RNA in situ analysis of 8.0 day embryos revealed that tek expression first becomes detectable in the developing yolk sac and a few small clusters of cells in the cephalic mesenchyme. This expression becomes more pronounced by Day 8.5, at which time significant hybridization can be observed in the mesodermal component of the amnion (outer cell layer) and yolk sac (inner cell layer) , as well as in the developing endocardium and the inner lining of the head veins and dorsal aortae (Figure 7A and 7B) . In addition, sagittal sections reveal numerous focal areas of hybridization throughout the cephalic mesenchyme in regions thought to contain developing vasculature, as well as a small number of tek- expressing cells extending beneath the ventral surface of the somites (Figure 7H and 7J) . Whole mount in situ hybridization analysis confirmed and extended the above observations, as well as provided a three dimensional perspective on tek expression during embryogenesis. Figure 8 shows tei expression in whole mount embryos; A., B., C. and D. tek expression in Day 8.0 embryos. E. tek mRNA distribution in a Day 9.5 embryo. F. En2 expression in a Day 8 embryo. I, II, III, first, second and third aortic arches; DA. dorsal aorta; E, endocardium; G, foregut pocket; H, heart; IS, intersegmental vessel; My, myocardium; ; NF, neural fold; OT; otic vesicle; V, vitelline vein; Y, yolk sac. Bars: 250 μm. Consistent with our observations with sectioned material, localized tek expression was not observed on embryonic Day 7. The first detectable expression was seen about the time of first somite formation when signal was observed in the yolk sac, head mesenchyme, and heart. In Day 8.5 embryos, tek was found to be expressed in these same areas, and in the paired dorsal aortae, the vitelline veins, and in the forming intersegmental vessels (Figure 8). By this time, tejfc expression was clearly confined to blood vessels within the embryo. On Day 9, tek expression was seen in addition, in the aortic arches and expression was very striking in the endocardium (Figure 8E) . Control hybridizations with an En-2 probe demonstrated the specificity of teifc RNA detection (Figure 8F) . EXAMPLE V Expression of tek in endothelial cell progenitors The observation that teifc is expressed between Day 8.0 and 8.5 in focal regions thought to represent developing blood vessels raised the possibility that tek might be expressed in endothelial cell progenitors. Indeed, close inspection of hybridized sections from 8 to 8.5 day embryos revealed that while the expression of tek in the maternal decidua is restricted to cells of an endothelial cell morphology, tek expressing cells in the embryo are of two morphologically distinct cell types. In the developing blood islands of the yolk sac, where tek expression is first detected, silver grains are localized predominantly to elongated cells with characteristic endothelial cell morphology (Figure 7C) . In contrast, within the cephalic mesenchyme, silver grains are frequently observed over large, round cells that, on the basis of similar morphology to cells described during avian embryogenesis (Pardanaud et al . , 1987; Coffin & Poole, 1988; Noden, 1989; Noden-, 1991), correspond to angioblasts, the presumptive progenitor of endothelial cells (Figure 7F) . Both cell types are observed in the developing endocardium (Figure 71) which, at later stages, is known to contain only fully mature endothelial cells. To characterize more precisely the staging of tek expression within the endothelial lineage, sections adjacent to those used for in situ hybridization were stained immunohistochemically for von Willebrand factor, a well characterized marker of mature endothelial cells (Jaffe, E.A., Hoyer, L.W. & Nachman, R.L. (1973). J. Cl in . Invest . , 52, 2757-2764; Hormia, M. , Lehto, V.-P. & Virtanen, I. (1984), Eur.J. Cell .Biol . , 33, 217-228). Figure 7B and H shows that whereas tek is expressed in both the maternal decidua and the embryo at Day 8.5, expression of von Willebrand factor is observed only in the tele-expressing, vascular endothelial cells of the maternal decidua (Figure 7D and 7E) . Hence tele expression precedes that of von Willebrand factor during embryogenesis. The same scenario is observed at later developmental stages during vascularization of individual organs. Figure 9 shows the expression of tek precedes that of von Willebrand factor in the developing leptomeninges; A. Absence of immunohistochemical staining of von Willebrand factor in Day 12.5 leptomeninges. Arrow denotes a large blood vessel faintly positive for von Willebrand factor. B. In situ detection of tek expression in Day 12.5 leptomeninges. C. Staining of von Willebrand factor in Day 14.5 leptomeninges. Day 14.5 leptomeninges were positive for tek expression (not shown) . M, leptomeninges. Bars: 200 μm. Figure 9 shows that in the 12.5 day embryo, the developing leptomeninges hybridizes strongly with tek but faiis to stain positive for von Willebrand factor. By Day 14.5, however, expression of von Willebrand factor can be readily detected in the leptomeninges. Assuming that there is not a significant lag between transcription and translation of von Willebrand factor, these observations, together with those on the morphology of tele-expressing cells, suggest that tek is expressed in both mature endothelial cells and their progenitors. EXAMPLE VI tek is expressed in adult vasculature While the above results establish that tek is expressed during vascularization of the embryo, it was also of interest to determine whether expression of tek is maintained in endothelial cells of the adult. In situ hybridization analysis of a section through the heart region of a 3 week-old mouse revealed that tek is expressed in the endocardium as well as in the endothelial lining of major blood vessels, both arteries and veins, connecting with the adult heart (Figure 10). Figure 10 shows the expression of tek in adult vasculature. A. Bright field illumination of a section through the upper heart region of a 3 week-old mouse hybridized with an [ 35 S]-labelled tek probe. Bar: 20 μm. B. and C. Bright field illumination showing tek expression in endothelial cells lining the artery and vein respectively. Bar: 1 μm. Immunohistochemical staining of adjacent sections revealed that structures positive for tek expression also stained positive for von Willebrand factor. A, artery; Bl, extravasated blood; T, trachea; V, vein.) . The intensity of the hybridization signal observed for these structures is considerably lower than that observed for the endocardium and blood vessels of 12.5 day embryos hybridized and processed in parallel. This could indicate that mature endothelial cells, which are thought to be resting, have a different quantitative or qualitative requirement for expression of tek. Determination of the initiation site of translation of tek Additional cDNA sequences spanning the entire tek cDNA were obtained by screening cDNA libraries using well established protocols (Sambrook et al, 1989, Molecular Cloning, A Laboratory Manual Cold Spring Harbor- Lab. Press). Analysis of the complete cDNA sequence allowed determination of the most probable start of translation for the following reasons: (1) The putative initiation codon (Methionine) is followed by a stretch of 23 amino acids which are of sufficient hydrophobicity that they could serve as a signal peptide. (2) The reading frame does not contain any stop codons for 1118 amino acids and the derived amino acid sequence contains primary sequence motifs that are characteristic of receptor tyrosine kinases. (3) the other two forward reading frames are not open for any significant distance and contain multiple stop codons. EXAMPLE VIII A DNA segment was isolated from a mouse genomic bacteriophage library using a 5'-prime probe, consisting of nucleotides 0 to 912 of the tek cDNA, which contained the initiation codon and untranslated sequences of tek using the procedures of Sambrook et al., 1989, Molecular Cloning, A Laboratory Manual. Cold Spring Harbour Lab. Press. The DNA segment was cloned in the plasmid pGEm72F + and propagated in E. coli K12. A 16 kb phage clone was shown by hybridization with this 5'-prime probe and sequence analysis using oligonucleotides specific for the cDNA sequence and the plasmid backbone, to contain a single exon with 175 bp homologous to the cDNA. A DNA fragment extending from the Bgl II restriction site located at nucleotide 110 of the cDNA to the nearest Kpn I in the phage was cloned upstream of the bacterial gene lacZ. This reporter construct containing 7.2 kb of the tek gene was microinjected into pronuclei of fertilized randomly bred CD-I mice using procedures as set out in Hogan et al., 1986, Manipulating the Mouse Embryo, A Laboratory Manual. Cold Spring Harbor Lab. Press. Three transgenic founder embryos were dissected from their foster mothers and yolk sac DNA analyzed for the presence of the transgene. Expression of the transgene was determined by the X-gal staining of whole embryos and subsequent sectioning of the embryos. Figure 12 shows expression of LacZ in Day 8.5 embryos and Figure 13 shows mRNA distribution in a Day 8.5 embryo. The 7.2 kb fragment was able to drive lacZ expression in endothelial cells that had previously been shown to express tek RNA (Figure 12) thus demonstrating that this DNA contained the tek promoter. Table 1 ne kinase cDNAs isolated b - TA RT Fr ι Cosegregation of the tek, brown, and pmv-23 loci in A x D strains. A x D strain Locus 1 2 3 6 7 8 9 1011121314151618202122232425262728 tek DDADDAAADADADDDDADDADDDD brown DDADDAAADAAADDDDADAADDDD pmv-23 DDADDADADADDDADDADDADDDA SEQUENCE LISTING (1) GENERAL INFORMATION: (i) APPLICANT: Mount Sinai Hospital Corporation Breitman, Martin L Dumont, Daniel J. _>.. Gradwohl, Gerard G (ii) TITLE OF INVENTION: Tissue Specific Transcriptional ■ *. Regulatory Element (iii) NUMBER OF SEQUENCES: 5 (iv) CORRESPONDENCE ADDRESS: (A) ADDRESSEE: Linda M. Kurdydyk, Bereskin & Parr (B) STREET: Box 401, 40 King Street West (C) CITY: Toronto (D) STATE: Ontario (E) COUNTRY: Canada (F) ZIP: M5H 3Y2 (v) COMPUTER READABLE FORM: (A) MEDIUM TYPE: Floppy disk (B) COMPUTER: IBM PC compatible (C) OPERATING SYSTEM: PC-DOS/MS-DOS (D) SOFTWARE: PatentIn Release #1.0, Version #1.25 (vi) CURRENT APPLICATION DATA: (A) APPLICATION NUMBER: (B) FILING DATE: 25-AUG-1993 (C) CLASSIFICATION: (viii) ATTORNEY/AGENT INFORMATION: (A) NAME: Kurdydyk, Linda M (B) REGISTRATION NUMBER: 34,971 (C) REFERENCE/DOCKET NUMBER: 3153-086/LMK (ix) TELECOMMUNICATION INFORMATION: (A) TELEPHONE: (416) 364-7311 (B) TELEFAX: (416) 361-1398 (C) TELEX: 06-23115 (2) INFORMATION FOR SEQ ID NO:l: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 4176 base pairs (B) TYPE: nucleic acid (C) STRANDEDNESS: single (D) TOPOLOGY: linear (ii) MOLECULE TYPE: cDNA (iii) HYPOTHETICAL: NO (iv) ANTI-SENSE: NO (v) FRAGMENT TYPE: N-terminal (vi) ORIGINAL SOURCE: (A) ORGANISM: Mus musculus (B) STRAIN: CD-I (D) DEVELOPMENTAL STAGE: Embryo (F) TISSUE TYPE: Heart (vii) IMMEDIATE SOURCE: (B) CLONE: tek (viii) POSITION IN GENOME: (A) CHROMOSOME/SEGMENT: 4 (B) MAP POSITION: Between the brown and pmv-23 loci (ix) F ve transmembrane kinasereceptor" (xi) SEQUENCE DESCRIPTION: SEQ ID NO:l: GCCAACTTGT AAACAAGAGC GAGTGGACCA TGCGAGCGGG AAGTCGCAAA GTTGTGAGTT 60 GTTGAAAGCT TCCCAGGGAC TCATGCTCAT CTGTGGACGC TGGATGGGGA GATCTGGGGA 120 AGT ATG GAC TCT TTA GCC GGC TTA GTT CTC TGT GGA GTC AGC TTG CTC 168 Met Asp Ser Leu Ala Gly Leu Val Leu Cys Gly Val Ser Leu Leu 1 5 10 15 CTT TAT GGA GTA GTA GAA GGC GCC ATG GAC CTG ATC TTG ATC AAT TCC 216 Leu Tyr Gly Val Val Glu Gly Ala Met Asp Leu lie Leu lie Asn Ser 20 25 30 CTA CCT CTT GTG TCT GAT GCC GAA ACA TCC CTC ACC TGC ATT GCC TCT 264 Leu Pro Leu Val Ser Asp Ala Glu Thr Ser Leu Thr Cys lie Ala Ser 35 40 45 GGG TGG CAC CCC CAT GAG CCC ATC ACC ATA GGA AGG GAC TTT GAA GCC 312 Gly Trp His Pro His Glu Pro lie Thr lie Gly Arg Asp Phe Glu Ala 50 55 60 TTA ATG AAC CAG CAC CAA GAT CCA CTG GAG GTT ACT CAA GAT GTG ACC 360 Leu Met Asn Gin His Gin Asp Pro Leu Glu Val Thr Gin Asp Val Thr 65 70 75 AGA GAA TGG GCG AAA AAA GTT GTT TGG AAG AGA GAA AAG GCC AGT AAG 408 Arg Glu Trp Ala Lys Lys Val Val Trp Lys Arg Glu Lys Ala Ser Lys 80 85 90 95 ATT AAT GGT GCT TAT TTC TGT GAA GGT CGA GTT CGA GGA CAG GCT ATA 456 lie Asn Gly Ala Tyr Phe Cys Glu Gly Arg Val Arg Gly Gin Ala lie 100 105 110 AGG ATA CGG ACC ATG AAG ATG CGT CAA CAA GCA TCC TTC CTA CCT GCT 504 Arg lie Arg Thr Met Lys Met Arg Gin Gin Ala Ser Phe Leu Pro Ala 115 120 125 ACT TTA ACT ATG ACC GTG GAC AGG GGA GAT AAT GTG AAC ATA TCT TTC 552 Thr Leu Thr Met Thr Val Asp Arg Gly Asp Asn Val Asn lie Ser Phe 130 135 140 AAA AAG GTG TTA ATT AAA GAA GAA GAT GCA GTG ATT TAC AAA AAT GGC 600 Lys Lys Val Leu lie Lys Glu Glu Asp Ala Val lie Tyr Lys Asn Gly 145 150 155 TCC TTC ATC CAC TCA GTG CCC CGG CAT GAA GTA CCT GAT ATT TTA GAA 648 Ser Phe lie His Ser Val Pro Arg His Glu Val Pro Asp lie Leu Glu 160 165 170 175 GTT CAC TTG CCG CAT GCT CAG CCC CAG GAT GCT GGT GTG TAC TCG GCC 696 Val His Leu Pro His Ala Gin Pro Gin Asp Ala Gly Val Tyr Ser Ala 180 185 190 AGG TAC ATA GGA GGA AAC CTG TTC ACC TCA GCC TTC ACC AGG CTG ATT 744 Arg Tyr lie Gly Gly Asn Leu Phe Thr Ser Ala Phe Thr Arg Leu lie 195 200 205 GTT CGG AGA TGT GAA GCT CAG AAG TGG GGG CCC GAC TGT AGC CGT CCT 792 Val Arg Arg Cys Glu Ala Gin Lys Trp Gly Pro Asp Cys Ser Arg Pro 210 215 220 TGT ACT ACT TGC AAG AAC AAT GGA GTC TGC CAT GAA GAT ACC GGG GAA 840 Cys Thr Thr Cys Lys Asn Asn Gly Val Cys His Glu Asp Thr Gly Glu 225 230 235 TGC ATT TGC CCT CCT GGG TTT ATG GGG AGA ACA TGT GAG AAA GCT TGT 888 Cys lie Cys Pro Pro Gly Phe Met Gly Arg Thr Cys Glu Lys Ala Cys 240 245 250 255 GAG CCG CAC ACA TTT GGC AGG ACC TGT AAA GAA AGG TGT AGT GGA CCA 936 Glu Pro His Thr Phe Gly Arg Thr Cys Lys Glu Arg Cys Ser Gly Pro 260 265 270 GAA GGA TGC AAG TCT TAT GTG TTC TGT CTC CCA GAC CCT TAC GGG TGT 984 Glu Gly Cys Lys Ser Tyr Val Phe Cys Leu Pro Asp Pro Tyr Gly Cys 275 280 285 TCC TGT GCC ACA GGC TGG AGG GGG TTG CAG TGC AAT GAA GCA TGC CCA 1032 Ser Cys Ala Thr Gly Trp Arg Gly Leu Gin Cys Asn Glu Ala Cys Pro 290 295 300 TCT GGT TAC TAC GGA CCA GAC TGT AAG CTC AGG TGC CAC TGT ACC AAT 1080 Ser Gly Tyr Tyr Gly Pro Asp Cys Lys Leu Arg Cys His Cys Thr Asn 305 310 315 GAA GAG ATA TGT GAT CGG TTC CAA GGA TGC CTC TGC TCT CAA GGA TGG 1128 Glu Glu lie Cys Asp Arg Phe Gin Gly Cys Leu Cys Ser Gin Gly Trp 320 325 330 335 CAA GGG CTG CAG TGT GAG AAA GAA GGC AGG CCA AGG ATG ACT CCA CAG 1176 Gin Gly Leu Gin Cys Glu Lys Glu Gly Arg Pro Arg Met Thr Pro Gin 340 345 350 ATA GAG GAT TTG CCA GAT CAC ATT GAA GTA AAC AGT GGA AAA TTT AAC 1224 lie Glu Asp Leu Pro Asp His lie Glu Val Asn Ser Gly Lys Phe Asn 355 360 365 CCC ATC TGC AAA GCC TCT GGG TGG CCA CTA CCT ACT AGT GAA GAA ATG 1272 Pro lie Cys Lys Ala Ser Gly Trp Pro Leu Pro Thr Ser Glu Glu Met 370 375 380 ACC CTA GTG AAG CCA GAT GGG ACA GTG CTC CAA CCA AAT GAC TTC AAC 1320 Thr Leu Val Lys Pro Asp Gly Thr Val Leu Gin Pro Asn Asp Phe Asn 385 390 395 TAT ACA GAT CGT TTC TCA GTG GCC ATA TTC ACT GTC AAC CGA GTC TTA 1368 Tyr Thr Asp Arg Phe Ser Val Ala lie Phe Thr Val Asn Arg Val Leu 400 405 410 415 CCT CCT GAC TCA GGA GTC TGG GTC TGC AGT GTG AAC ACA GTG GCT GGG 1416 Pro Pro Asp Ser Gly Val Trp Val Cys Ser Val Asn Thr Val Ala Gly 420 425 430 ATG GTG GAA AAG CCT TTC AAC ATT TCC GTC AAA GTT CTT CCA GAG CCC 1464 Met Val Glu Lys Pro Phe Asn lie Ser Val Lys Val Leu Pro Glu Pro 435 440 445 CTG CAC GCC CCA AAT GTG ATT GAC ACT GGA CAT AAC TTT GCT ATC ATC 1512 Leu His Ala Pro Asn Val lie Asp Thr Gly His Asn Phe Ala lie lie 450 455 460 AAT ATC AGC TCT GAG CCT TAC TTT GGG GAT GGA CCC ATC AAA TCC AAG 1560 Asn lie Ser Ser Glu Pro Tyr Phe Gly Asp Gly Pro lie Lys Ser Lys 465 470 475 AAG CTT TTC TAT AAA CCT GTC AAT CAG GCC TGG AAA TAC ATT GAA GTG 1608 Lys Leu Phe Tyr Lys Pro Val Asn Gin Ala Trp Lys Tyr lie Glu Val 480 485 490 495 ACG AAT GAG ATT TTC ACT CTC AAC TAC TTG GAG CCG CGG ACT GAC TAC 1656 Thr Asn Glu lie Phe Thr Leu Asn Tyr Leu Glu Pro Arg Thr Asp Tyr 500 505 510 GAG CTG TGT GTG CAG CTG GCC CGT CCT GGA GAG GGT GGA GAA GGG CAT 1704 Glu Leu Cys Val Gin Leu Ala Arg Pro Gly Glu Gly Gly Glu Gly His 515 520 525 CCT GGG CCT GTG AGA CGA TTT ACA ACA GCG TGT ATC GGA CTC CCT CCT 1752 Pro Gly Pro Val Arg Arg Phe Thr Thr Ala Cys lie Gly Leu Pro Pro 530 535 540 CCA AGA GGT CTC AGT CTC CTG CCA AAA AGC CAG ACA GCT CTA AAT TTG 1800 Pro Arg Gly Leu Ser Leu Leu Pro Lys Ser Gin Thr Ala Leu Asn Leu 545 550 555 ACT TGG CAA CCG ATA TTT ACA AAC TCA GAA GAT GAA TTT TAT GTG GAA 1848 Thr Trp Gin Pro lie Phe Thr Asn Ser Glu Asp Glu Phe Tyr Val Glu 560 565 570 575 GTC GAG AGG CGA TCC CTG CAA ACA ACA AGT GAT CAG CAG AAC ATC AAA 1896 Val Glu Arg Arg Ser Leu Gin Thr Thr Ser Asp Gin Gin Asn lie Lys 580 585 590 GTG CCT GGG AAC CTG ACC TCG GTG CTA CTG AGC AAC TTA GTC CCC AGG 1944 Val Pro Gly Asn Leu Thr Ser Val Leu Leu Ser Asn Leu Val Pro Arg 595 600 605 GAG CAG TAC ACA GTC CGA GCT AGA GTC AAC ACC AAG GCG CAG GGG GAG 1992 Glu Gin Tyr Thr Val Arg Ala Arg Val Asn Thr Lys Ala Gin Gly Glu 610 615 620 TGG AGT GAA GAA CTC AGG GCC TGG ACC CTT AGT GAC ATT CTC CCT CCT 2040 Trp Ser Glu Glu Leu Arg Ala Trp Thr Leu Ser Asp lie Leu Pro Pro 625 630 635 CAA CCA GAA AAC ATC AAG ATC TCC AAC ATC ACT GAC TCC ACA GCT ATG 2088 Gin Pro Glu Asn lie Lys lie Ser Asn lie Thr Asp Ser Thr Ala Met 640 645 650 655 GTT TCT TGG ACA ATA GTG GAT GGC TAT TCG ATT TCT TCC ATC ATC ATC 2136 Val Ser Trp Thr lie Val Asp Gly Tyr Ser lie Ser Ser lie lie lie 660 665 670 CGG TAT AAG GTT CAG GGC AAA AAT GAA GAC CAG CAC ATT GAT GTG AAG 2184 Arg Tyr Lys Val Gin Gly Lys Asn Glu Asp Gin His lie Asp Val Lys 675 680 685 ATC AAG AAT GCT ACC GTT ACT CAG TAC CAG CTC AAG GGC CTA GAG CCA 2232 lie Lys Asn Ala Thr Val Thr Gin Tyr Gin Leu Lys Gly Leu Glu Pro 690 695 700 GAG ACT ACA TAC CAT GTG GAT ATT TTT GCT GAG AAC AAC ATA GGA TCA 2280 Glu Thr Thr Tyr His Val Asp lie Phe Ala Glu Asn Asn lie Gly Ser 705 710 715 AGC AAC CCA GCC TTT TCT CAT GAA CTG AGG ACG CTT CCA CAT TCC CCA 2328 Ser Asn Pro Ala Phe Ser His Glu Leu Arg Thr Leu Pro His Ser Pro 720 725 730 735 GGC TCT GCA GAC CTC GGA GGG GGA AAG ATG CTA CTC ATA GCC ATC CTT 2376 Gly Ser Ala Asp Leu Gly Gly Gly Lys Met Leu Leu lie Ala lie Leu 740 745 750 GGG TCG GCT GGA ATG ACT TGC ATC ACC GTG CTG TTG GCG TTT CTG ATT 2424 Gly Ser Ala Gly Met Thr Cys lie Thr Val Leu Leu Ala Phe Leu lie 755 760 765 ATG TTG CAA CTG AAG AGA GCA AAT GTC CAA AGG AGA ATG GCT CAG GCA 2472 Met Leu Gin Leu Lys Arg Ala Asn Val Gin Arg Arg Met Ala Gin Ala 770 775 780 TTC CAG AAC AGA GAA GAA CCA GCT GTG CAG TTT AAC TCA GGA ACT CTG 2520 Phe Gin Asn Arg Glu Glu Pro Ala Val Gin Phe Asn Ser Gly Thr Leu 785 790 795 GCC CTT AAC AGG AAG GCC AAA AAC AAT CCA GAT CCC ACA ATT TAT CCT 2568 Ala Leu Asn Arg Lys Ala Lys Asn Asn Pro Asp Pro Thr lie Tyr Pro 800 805 810 815 GTG CTT GAC TGG AAT GAC ATC AAG TTT CAA GAC GTG ATC GGA GAG GGC 2616 Val Leu Asp Trp Asn Asp lie Lys Phe Gin Asp Val He Gly Glu Gly 820 825 830 AAC TTT GGC CAG GTT CTG AAG GCA CGC ATC AAG AAG GAT GGG TTA CGG 2664 Asn Phe Gly Gin Val Leu Lys Ala Arg He Lys Lys Asp Gly Leu Arg 835 840 845 ATG GAT GCC GCC ATC AAG AGG ATG AAA GAG TAT GCC TCC AAA GAT GAT 2712 Met Asp Ala Ala He Lys Arg Met Lys Glu Tyr Ala Ser Lys Asp Asp 850 855 860 CAC AGG GAC TTC GCA GGA GAA CTG GAG GTT CTT TGT AAA CTT GGA CAC 2760 His Arg Asp Phe Ala Gly Glu Leu Glu Val Leu Cys Lys Leu Gly His 865 870 875 CAT CCA AAC ATC ATT AAT CTC TTG GGA GCA TGT GAA CAC CGA GGC TAT 2808 His Pro Asn He He Asn Leu Leu Gly Ala Cys Glu His Arg Gly Tyr 880 885 890 895 TTG TAC CTA GCT ATT GAG TAT GCC CCG CAT GGA AAC CTC CTG GAC TTC 2856 Leu Tyr Leu Ala He Glu Tyr Ala Pro His Gly Asn Leu Leu Asp Phe 900 905 910 CTG CGT AAG AGC AGA GTG CTA GAG ACA GAC CCT GCT TTT GCC ATC GCC 2904 Leu Arg Lys Ser Arg Val Leu Glu Thr Asp Pro Ala Phe Ala He Ala 915 920 925 AAC AGT ACA GCT TCC ACA CTG TCC TCC CAA CAG CTT CTT CAT TTT GCT 2952 Asn Ser Thr Ala Ser Thr Leu Ser Ser Gin Gin Leu Leu His Phe Ala 930 935 940 GCA GAT GTG GCC CGG GGG ATG GAC TAC TTG AGC CAG AAA CAG TTT ATC 3000 Ala Asp Val Ala Arg Gly Met Asp Tyr Leu Ser Gin Lys Gin Phe He 945 950 955 CAC AGG GAC CTG GCT GCC AGA AAC ATT TTA GTT GGT GAA AAC TAC ATA 3048 His Arg Asp Leu Ala Ala Arg Asn He Leu Val Gly Glu Asn Tyr He 960 965 970 975 GCC AAA ATA GCA GAT TTT GGA TTG TCA CGA GGT CAA GAA GTG TAT GTG 3096 Ala Lys He Ala Asp Phe Gly Leu Ser Arg Gly Gin Glu Val Tyr Val 980 985 990 AAA AAG ACA ATG GGA AGG CTC CCA GTG CGT TGG ATG GCA ATC GAA TCA 3144 Lys Lys Thr Met Gly Arg Leu Pro Val Arg Trp Met Ala He Glu Ser 995 1000 1005 CTG AAC TAT AGT GTC TAT ACA ACC AAC AGT GAT GTC TGG TCC TAT GGT 3192 Leu Asn Tyr Ser Val Tyr Thr Thr Asn Ser Asp Val Trp Ser Tyr Gly 1010 1015 1020 GTA TTG CTC TGG GAG ATT GTT AGC TTA GGA GGC ACC CCC TAC TGC GGC 3240 Val Leu Leu Trp Glu He Val Ser Leu Gly Gly Thr Pro Tyr Cys Gly 1025 1030 1035 ATG ACG TGC GCG GAG CTC TAT GAG AAG CTA CCC CAG GGC TAC AGG CTG 3288 Met Thr Cys Ala Glu Leu Tyr Glu Lys Leu Pro Gin Gly Tyr Arg Leu 1040 1045 1050 1055 GAG AAG CCC CTG AAC TGT GAT GAT GAG GTG TAT GAT CTA ATG AGA CAG 3336 Glu Lys Pro Leu Asn Cys Asp Asp Glu Val Tyr Asp Leu Met Arg Gin 1060 1065 1070 TGC TGG AGG GAG AAG CCT TAT GAG AGA CCA TCA TTT GCC CAG ATA TTG 3384 Cys Trp Arg Glu Lys Pro Tyr Glu Arg Pro Ser Phe Ala Gin He Leu 1075 1080 1085 GTG TCC TTA AAC AGG ATG CTG GAA GAA CGG AAG ACA TAC GTG AAC ACC 3432 Val Ser Leu Asn Arg Met Leu Glu Glu ^ Arg Lys Thr Tyr Val Asn Thr 1090 1095 1100 ACA CTG TAT GAG AAG TTT ACC TAT GCA GGA ATT GAC TGC TCT GCG GAA 3480 Thr Leu Tyr Glu Lys Phe Thr Tyr Ala Gly He Asp Cys Ser Ala Glu 1105 1110 1115 GAA GCA GCC TAGAGCAGAA CTCTTCATGT ACAACGGCCA TTTCTCCTCA 3529 Glu Ala Ala 1120 CTGGCGCGAG AGCCTTGACA CCTGTACCAA GCAAGCCACC CACTGCCAAG AGATGTGATA 3589 TATAAGTGTA TATATTGTGC TGTGTTTGGG ACCCTCCTCA TACAGCTCGT GCGGATCTGC 3649 AGTGTGTTCT GACTCTAATG TGACTGTATA TACTGCTCGG AGTAAGAATG TGCTAAGATC 3709 AGAATGCCTG TTCGTGGTTT CATATAATAT ATTTTTCTAA AAGCATAGAT TGCACAGGAA 3769 GGTATGAGTA CAAATACTGT AATGCATAAC TTGTTATTGT CCTAGATGTG TTTGACATTT 3829 TTCCTTTACA ACTGAATGCT ATAAAAGTGT TTTGCTGTGT GCGCGTAAGA TACTGTTCGT 3889 TAAAATAAGC ATTCCCTTGA CAGCACAGGA AGAAAAGCGA GGGAAATGTA TGGATTATAT 3949 — TAAATGTGGG TTACTACACA AGAGGCCGAA CATTCCAAGT AGCAGAAGAG AGGGTCTCTC 4009 AACTCTGCTC CTCACCTGCA GAAGCCAGTT TGTTTGGCCA TGTGACAATT GTCCTGTGTT 4069 TTTATAGCAC CCAAATCATT CTAAAATATG AACATCTAAA AACTTTGCTA GGAGACTAAG 4129 AACCTTTGGA GAGATAGATA TAAGTACGGT CAAAAAACAA AACTGCG 4176 (2) INFORMATION FOR SEQ ID NO:2: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 1122 amino acids (B) TYPE: amino acid (D) TOPOLOGY: linear (ii) MOLECULE TYPE: protein ( i) SEQUENCE DESCRIPTION: SEQ ID NO:2: Met Asp Ser Leu Ala Gly Leu Val Leu Cys Gly Val Ser Leu Leu Leu 1 5 10 15 Tyr Gly Val Val Glu Gly Ala Met Asp Leu He Leu He Asn Ser Leu 20 25 30 Pro Leu Val Ser Asp Ala Glu Thr Ser Leu Thr Cys He Ala Ser Gly 35 40 45 Trp His Pro His Glu Pro He Thr He Gly Arg Asp Phe Glu Ala Leu 50 55 60 Met Asn Gin His Gin Asp Pro Leu Glu Val Thr Gin Asp Val Thr Arg 65 70 75 80 Glu Trp Ala Lys Lys Val Val Trp Lys Arg Glu Lys Ala Ser Lys He 85 90 95 Asn Gly Ala Tyr Phe Cys Glu Gly Arg Val Arg Gly Gin Ala He Arg 100 105 110 He Arg Thr Met Lys Met Arg Gin Gin Ala Ser Phe Leu Pro Ala Thr 115 120 125 Leu Thr Met Thr Val Asp Arg Gly Asp Asn Val Asn He Ser Phe Lys 130 135 140 Lys Val Leu He Lys Glu Glu Asp Ala Val He Tyr Lys Asn Gly Ser 145 150 155 160 Phe He His Ser Val Pro Arg His Glu Val Pro Asp He Leu Glu Val 165 170 175 His Leu Pro His Ala Gin Pro Gin Asp Ala Gly Val Tyr Ser Ala Arg 180 185 190 Tyr He Gly Gly Asn Leu Phe Thr Ser Ala Phe Thr Arg Leu He Val 195 200 205 Arg Arg Cys Glu Ala Gin Lys Trp Gly Pro Asp Cys Ser Arg Pro Cys 210 215 220 Thr Thr Cys Lys Asn Asn Gly Val Cys His Glu Asp Thr Gly Glu Cys 225 230 235 240 He Cys Pro Pro Gly Phe Met Gly Arg Thr Cys Glu Lys Ala Cys Glu 245 250 255 Pro His Thr Phe Gly Arg Thr Cys Lys Glu Arg Cys Ser Gly Pro Glu 260 265 270 Gly Cys Lys Ser Tyr Val Phe Cys Leu Pro Asp Pro Tyr Gly Cys Ser 275 280 285 Cys Ala Thr Gly Trp Arg Gly Leu Gin Cys Asn Glu Ala Cys Pro Ser 290 295 300 Gly Tyr Tyr Gly Pro Asp Cys Lys Leu Arg Cys His Cys Thr Asn Glu 305 310 315 320 Glu He Cys Asp Arg Phe Gin Gly Cys Leu Cys Ser Gin Gly Trp Gin 325 330 335 Gly Leu Gin Cys Glu Lys Glu Gly Arg Pro Arg Met Thr Pro Gin He 340 345 350 Glu Asp Leu Pro Asp His He Glu Val Asn Ser Gly Lys Phe Asn Pro 355 360 365 He Cys Lys Ala Ser Gly Trp Pro Leu Pro Thr Ser Glu Glu Met Thr 370 375 380 Leu Val Lys Pro Asp Gly Thr Val Leu Gin Pro Asn Asp Phe Asn Tyr 385 390 395 400 Thr Asp Arg Phe Ser Val Ala He Phe Thr Val Asn Arg Val Leu Pro 405 410 415 Pro Asp Ser Gly Val Trp Val Cys Ser Val Asn Thr Val Ala Gly Met 420 425 430 Val Glu Lys Pro Phe Asn He Ser Val Lys Val Leu Pro Glu Pro Leu 435 440 445 His Ala Pro Asn Val He Asp Thr Gly His Asn Phe Ala He He Asn 450 455 460 He Ser Ser Glu Pro Tyr Phe Gly Asp Gly Pro He Lys Ser Lys Lys 465 470 475 480 Leu Phe Tyr Lys Pro Val Asn Gin Ala Trp Lys Tyr He Glu Val Thr 485 490 495 Asn Glu He Phe Thr Leu Asn Tyr Leu Glu Pro Arg Thr Asp Tyr Glu 500 505 510 Leu Cys Val Gin Leu Ala Arg Pro Gly Glu Gly Gly Glu Gly His Pro 515 520 525 Gly Pro Val Arg Arg Phe Thr Thr Ala Cys He Gly Leu Pro Pro Pro 530 535 540 Arg Gly Leu Ser Leu Leu Pro Lys Ser Gin Thr Ala Leu Asn Leu Thr 545 550 555 560 Trp Gin Pro He Phe Thr Asn Ser Glu Asp Glu Phe Tyr Val Glu Val 565 570 575 Glu Arg Arg Ser Leu Gin Thr Thr Ser Asp Gin Gin Asn He Lys Val 580 585 590 Pro Gly Asn Leu Thr Ser Val Leu Leu Ser Asn Leu Val Pro Arg Glu 595 600 605 Gin Tyr Thr Val Arg Ala Arg Val Asn Thr Lys Ala Gin Gly Glu Trp 610 615 620 Ser Glu Glu Leu Arg Ala Trp Thr Leu Ser Asp He Leu Pro Pro Gin 625 630 635 640 Pro Glu Asn He Lys He Ser Asn He Thr Asp Ser Thr Ala Met Val 645 650 655 Ser Trp Thr He Val Asp Gly Tyr Ser He Ser Ser He He He Arg 660 665 670 Tyr Lys Val Gin Gly Lys Asn Glu Asp Gin His He Asp Val Lys He 675 680 685 Lys Asn Ala Thr Val Thr Gin Tyr Gin Leu Lys Gly Leu Glu Pro Glu 690 695 700 Thr Thr Tyr His Val Asp He Phe Ala Glu Asn Asn He Gly Ser Ser 705 710 715 720 Asn Pro Ala Phe Ser His Glu Leu Arg Thr Leu Pro His Ser Pro Gly 725 730 735 Ser Ala Asp Leu Gly Gly Gly Lys Met Leu Leu He Ala He Leu Gly 740 745 750 Ser Ala Gly Met Thr Cys He Thr Val Leu Leu Ala Phe Leu He Met 755 760 765 Leu Gin Leu Lys Arg Ala Asn Val Gin Arg Arg Met Ala Gin Ala Phe 770 775 780 Gin Asn Arg Glu Glu Pro Ala Val Gin Phe Asn Ser Gly Thr Leu Ala 785 790 795 800 Leu Asn Arg Lys Ala Lys Asn Asn Pro Asp Pro Thr He Tyr Pro Val 805 810 815 Leu Asp Trp Asn Asp He Lys Phe Gin Asp Val He Gly Glu Gly Asn 820 825 830 Phe Gly Gin Val Leu Lys Ala Arg He Lys Lys Asp Gly Leu Arg Met 835 840 845 Asp Ala Ala He Lys Arg Met Lys Glu Tyr Ala Ser Lys Asp Asp His 850 855 860 Arg Asp Phe Ala Gly Glu Leu Glu Val Leu Cys Lys Leu Gly His His 865 870 875 880 Pro Asn He He Asn Leu Leu Gly Ala Cys Glu His Arg Gly Tyr Leu 885 890 895 Tyr Leu Ala He Glu Tyr Ala Pro His Gly Asn Leu Leu Asp Phe Leu 900 905 910 Arg Lys Ser Arg Val Leu Glu Thr Asp Pro Ala Phe Ala He Ala Asn 915 920 925 Ser Thr Ala Ser Thr Leu Ser Ser Gin Gin Leu Leu His Phe Ala Ala 930 935 940 Asp Val Ala Arg Gly Met Asp Tyr Leu Ser Gin Lys Gin Phe He His 945 950 955 960 Arg Asp Leu Ala Ala Arg Asn He Leu Val Gly Glu Asn Tyr He Ala 965 970 975 Lys He Ala Asp Phe Gly Leu Ser Arg Gly Gin Glu Val Tyr Val Lys 980 985 990 Lys Thr Met Gly Arg Leu Pro Val Arg Trp Met Ala He Glu Ser Leu 995 1000 1005 Asn Tyr Ser Val Tyr Thr Thr Asn Ser Asp Val Trp Ser Tyr Gly Val 1010 1015 1020 Leu Leu Trp Glu He Val Ser Leu Gly Gly Thr Pro Tyr -Gys Gly Met 1025 1030 1035 1040 Thr Cys Ala Glu Leu Tyr Glu Lys Leu Pro Gin Gly Tyr Arg Leu Glu 1045 1050 1055 Lys Pro Leu Asn Cys Asp Asp Glu Val Tyr Asp Leu Met Arg Gin Cys 1060 1065 1070 Trp Arg Glu Lys Pro Tyr Glu Arg Pro Ser Phe Ala Gin He Leu Val 1075 1080 1085 Ser Leu Asn Arg Met Leu Glu Glu Arg Lys Thr Tyr Val Asn Thr Thr 1090 1095 1100 Leu Tyr Glu Lys Phe Thr Tyr Ala Gly He Asp Cys Ser Ala Glu Glu 1105 1110 1115 1120 Ala Ala (2) INFORMATION FOR SEQ ID NO:3: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 1590 base pairs (B) TYPE: nucleic acid (C) STRANDEDNESS: single (D) TOPOLOGY: linear (ii) MOLECULE TYPE: cDNA (vi) ORIGINAL SOURCE: (A) ORGANISM: Mus musculus (D) DEVELOPMENTAL STAGE: Embryo (vii) IMMEDIATE SOURCE: (A) LIBRARY: murine embryonic lambda gtlO cDNA library (B) CLONE: 1.6kb clone (viii) POSITION IN GENOME: (A) CHROMOSOME/SEGMENT: 4 (B) MAP POSITION: Between the brown and pmv-23 loci (ix) F (xi) SEQUENCE DESCRIPTION: SEQ ID NO:3: ATC AAG TTT CAA GAC GTG ATC GGA GAG GGC AAC TTT GGC CAG GTT CTG 48 He Lys Phe Gin Asp Val He Gly Glu Gly Asn Phe Gly Gin Val Leu 1 5 10 15 AAG GCA CGC ATC AAG AAG GAT GGG TTA CGG ATG GAT GCC GCC ATC AAG 96 Lys Ala Arg He Lys Lys Asp Gly Leu Arg Met Asp Ala Ala He Lys 20 25 30 AGG ATG AAA GAG TAT GCC TCC AAA GAT GAT CAC AGG GAC TTC GCA GGA 144 Arg Met Lys Glu Tyr Ala Ser Lys Asp Asp His Arg Asp Phe Ala Gly 35 40 45 GAA CTG GAG GTT CTT TGT AAA CTT GGA CAC CAT CCA AAC ATC ATT AAT 192 Glu Leu Glu Val Leu Cys Lys Leu Gly His His Pro Asn He He Asn 50 55 60 CTC TTG GGA GCA TGT GAA CAC CGA GGC TAT TTG TAC CTA GCT ATT GAG 240 Leu Leu Gly Ala Cys Glu His Arg Gly Tyr Leu Tyr Leu Ala He Glu 65 70 75 80 TAT GCC CCG CAT GGA AAC CTC CTG GAC TTC CTG CGT AAG AGC AGA GTG 288 Tyr Ala Pro His Gly Asn Leu Leu Asp Phe Leu Arg Lys Ser Arg Val 85 90 95 CTA GAG ACA GAC CCT GCT TTT GCC ATC GCC AAC AGT ACA GCT TCC ACA 336 Leu Glu Thr Asp Pro Ala Phe Ala He Ala Asn Ser Thr Ala Ser Thr 100 105 110 ACC TAT GCA GGA ATT GAC TGC TCT GCG GAA GAA GCA GCC TAGAGCAGAA 913 Thr Tyr Ala Gly He Asp Cys Ser Ala Glu Glu Ala Ala 290 295 300 CTCTTCATGT ACAACGGCCA TTTCTCCTCA CTGGCGCGAG AGCCTTGACA CCTGTACCAA 973 GCAAGCCACC CACTGCCAAG AGATGTGATA TATAAGTGTA TATATTGTGC TGTGTTTGGG 1033 ACCCTCCTCA TACAGCTCGT GCGGATCTGC AGTGTGTTCT GACTCTAATG TGACTGTATA 1093 TACTGCTCGG AGTAAGAATG TGCTAAGATC AGAATGCCTG TTCGTGGTTT CATATAATAT 1153 ATTTTTCTAA AAGCATAGAT TGCACAGGAA GGTATGAGTA CAAATACTGT AATGCATAAC 1213 TTGTTATTGT CCTAGATGTG TTTGACATTT TTCCTTTACA ACTGAATGCT ATAAAAGTGT 1273 TTTGCTGTGT GCGCGTAAGA TACTGTTCGT TAAAATAAGC ATTCCCTTGA CAGCACAGGA 1333 AGAAAAGCGA GGGAAATGTA TGGATTATAT TAAATGTGGG TTACTACACA AGAGGCCGAA 1393 CATTCCAAGT AGCAGAAGAG AGGGTCTCTC AACTCTGCTC CTCACCTGCA GAAGCCAGTT 1453 TGTTTGGCCA TGTGACAATT GTCCTGTGTT TTTATAGCAC CCAAATCATT CTAAAATATG 1513 AACATCTAAA AACTTTGCTA GGAGACTAAG AACCTTTGGA GAGATAGATA TAAGTACGGT 1573 CAAAAAACAA AACTGCG 1590 (2) INFORMATION FOR SEQ ID NO:4: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 301 amino acids (B) TYPE: amino acid (D) TOPOLOGY: linear (ii) MOLECULE TYPE: protein (xi) SEQUENCE DESCRIPTION: SEQ ID NO:4: He Lys Phe Gin Asp Val He Gly Glu Gly Asn Phe Gly Gin Val Leu 1 5 10 15 Lys Ala Arg He Lys Lys Asp Gly Leu Arg Met Asp Ala Ala He Lys 20 25 30 Arg Met Lys Glu Tyr Ala Ser Lys Asp Asp His Arg Asp Phe Ala Gly 35 40 45 Glu Leu Glu Val Leu Cys Lys Leu Gly His His Pro Asn He He Asn 50 55 60 Leu Leu Gly Ala Cys Glu His Arg Gly Tyr Leu Tyr Leu Ala He Glu 65 70 75 80 Tyr Ala Pro His Gly Asn Leu Leu Asp Phe Leu Arg Lys Ser Arg Val 85 90 95 Leu Glu Thr Asp Pro Ala Phe Ala He Ala Asn Ser Thr Ala Ser Thr 100 105 110 Leu Ser Ser Gin Gin Leu Leu His Phe Ala Ala Asp Val Ala Arg Gly 115 120 125 Met Asp Tyr Leu Ser Gin Lys Gin Phe He His Arg Asp Leu Ala Ala 130 135 140 Arg Asn He Leu Val Gly Glu Asn Tyr He Ala Lys He-Ala Asp Phe 145 150 155 160 Gly Leu Ser Arg Gly Gin Glu Val Tyr Val Lys Lys Thr Met Gly Arg 165 170 175 Leu Pro Val Arg Trp Met Ala He Glu Ser Leu Asn Tyr Ser Val Tyr 180 185 190 Thr Thr Asn Ser Asp Val Trp Ser Tyr Gly Val Leu Leu Trp Glu He 195 200 205 Val Ser Leu Gly Gly Thr Pro Tyr Cys Gly Met Thr Cys Ala Glu Leu 210 215 220 Tyr Glu Lys Leu Pro Gin Gly Tyr Arg Leu Glu Lys Pro Leu Asn Cys 225 230 235 240 Asp Asp Glu Val Tyr Asp Leu Met Arg Gin Cys Trp Arg Glu Lys Pro 245 250 255 Tyr Glu Arg Pro Ser Phe Ala Gin He Leu Val Ser Leu Asn Arg Met 260 265 270 Leu Glu Glu Arg Lys Thr Tyr Val Asn Thr Thr Leu Tyr Glu Lys Phe 275 280 285 Thr Tyr Ala Gly He Asp Cys Ser Ala Glu Glu Ala Ala 290 295 300 (2) INFORMATION FOR SEQ ID NO:5: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 847 base pairs (B) TYPE: nucleic acid (C) STRANDEDNESS: single (D) TOPOLOGY: linear (ii) MOLECULE TYPE: DNA (genomic) (vi) ORIGINAL SOURCE: (A) ORGANISM: Mus musculus (vii) IMMEDIATE SOURCE: (A) LIBRARY: mouse genomic bacteriophage library (viii) POSITION IN GENOME: (A) CHROMOSOME/SEGMENT: 4 (B) MAP POSITION: Between the brown and pmv-23 loci (xi) SEQUENCE DESCRIPTION: SEQ ID NO:5: GCAAGTGCTG CTCCCCGTGC CCCAAAGCCC CTTCTGTCAG GGATCCCAAA TGCACCCCAG 60 AGAACAGCTT AGCCTGCAAG GGCTGGTCCT CATCGCATAC CATACATAGT GGAGGCTTGT 120 TATTCAATTC CTGGCCTATG AGAGGATACC CCTATTGTTC CTGAAAATGC TGACCAGGAC 180 CTTACTTGTA ACAAAGATCC CTCTGCCCCA CAATCCAGTT AAGGCAGGAG CAGGACCGGA 240 GCAGGAGCAG AAGATAAGCC TTGGATGAAG GGCAAGATGG ATAGGGCTCG CTCTGCCCCA 300 AGCCCTGCTG ATACCAAGTG CCTTTAAGAT ACAGCCTTTC CCATCCTAAT CTGCAAAGGA 360 AACAGGAAAA AGGAACTTAA CCCTCCCTGT GCTCAGACAG AAATGAGACT GTTACCGCCT 420 GCTTCTGTGG TGTTTCTCCT TGCCGCCAAC TTGTAAACAA GAGCGAGTGG ACCATGAGAG 480 CGGGAAGTCG CAAAGTTGTG AGTTGTTGAA AGCTTCCCAG GGACTCATGC TCATCTGTGG 540 ACGCTGGATG GGGAGATCTG GGGAAGTATG GACTCTTTAG CCGGCTTAGT TCTCTGTGGA 600 GTCAGCTTGC TCCTTTATGG TAAGTTTTGG CTTGATGTTT ATTTGTGTGT GTGTGTCATG 660 TTTTAACAAC AGTGACTTCT CGCCATTCTC TCTCTCACCA AACCTTCGAT TTGGTGACCC 720 TGACACTGCT TTTCTGAGAC TCTCCAGTTT ACACATGGCA ACGGTTTTGA AGTTCAGATT 780 CCAGCGGCAC CAGCTGGTTT TCAGCCATCT TCTTGTAGAC AGATGCTGCC TTCCTGGGTT 840 GCCACGG 847 88

Claims: WE CLAIM: 1. An isolated transcriptional regulatory element which is capable of directing expression of a gene specifically in cells of the endothelial lineage. 2. An isolated transcriptional regulatory element as claimed in claim 1, comprising the initiation codon and untranslated sequences of tek. 3. An isolated transcriptional regulatory element as claimed in claim 2, which is a 7.2 kb fragment extending from the Bgl II site to the Kpn I site as shown in Figure 3. 4. A recombinant molecule adapted for transformation of a host cell comprising a transcriptional regulatory element as claimed in claim 1 and a gene operatively linked thereto. 5. A recombinant molecule as claimed in claim 4 wherein the gene is a reporter gene. 6. A recombinant molecule as claimed in claim 4 wherein the gene encodes a toxic or therapeutic substance or an angiogenic factor. 7. A recombinant molecule comprising a transcriptional regulatory element as claimed in claim 1 operatively linked to a gene and a reporter gene. 8. A transformant host cell including a recombinant molecule as claimed in claim 4, 5, 6 or 7. 9. A cell line comprising transformant host cells including a recombinant molecule as claimed in claim 4, 5, 6 or 7. 10. A method of producing a transgenic non-human mammal characterized as having a plurality of cells containing a recombinant molecule as claimed in claim 4 or 5, or an ancestor of the mammal at an embryonic stage, comprising (a) introducing a recombinant molecule as claimed in claim 4 or 5 into a pronucleus of a mammalian zygote by microinjection , said zygote being capable of development into a mammal, thereby obtaining a genetically transformed zygote; (b) transplanting an embryo derived from the genetically transformed zygote into a pseudo- pregnant female capable of bearing the embryo to term and (c) if desired allowing the embryo to develop to term. 11. A method of determining the affect of a substance on cells of the endothelial lineage comprising producing a transgenic non-human mammal characterized as having a plurality of cells containing a- recombinant molecule comprising the transcriptional regulatory element of the invention operatively linked to a gene encoding the substance, or an ancestor of the mammal at an embryonic stage, comprising (a) introducing the recombinant molecule into a pronucleus of a mammalian zygote by microinjection, said zygote being capable of development into a mammal, thereby obtaining a genetically transformed zygote; (b) transplanting an embryo derived from the genetically transformed zygote into a pseudo-pregnant female capable of bearing the embryo to term and (c) isolating the embryo or allowing the embryo to develop to term, and (d) determining the affect of the substance on cells of the endothelial lineage by comparison to a control. 12. A method of determining the affect of a substance on cells of the endothelial lineage comprising producing a transgenic non-human mammal characterized as having a plurality of cells containing a recombinant molecule comprising the transcriptional regulatory element of the invention operatively linked to a gene and a reporter gene encoding a phenotype which is not displayed by the mammal, or an ancestor of the mammal at an embryonic stage, comprising (a) introducing the DNA construct into a pronucleus of a mammalian zygote by microinjection, said zygote being capable of development into a mammal, thereby obtaining a genetically transformed zygote; (b) transplanting an embryo derived from the genetically transformed zygote into a pseudo-pregnant female capable of bearing the embryo to term and (c) isolating the embryo or allowing the embryo to develop to term, and (d) assaying for the phenotype of the reporter gene in the embryo or transgenic non-human mammal to determine the pattern and extent of expression of the gene, and (e) determining the affect of the substance on cells of the endothelial lineage by comparison to a control. 13. A transgenic non-human mammal all of whose germ cells and somatic cells contain a recombinant molecule introduced into the mammal, or an ancestor of the mammal at an embryonic stage, the recombinant molecule comprising a transcriptional regulatory element as claimed in claim 1, 2 or 3. 14. A method of using the transcriptional regulatory element as claim 1 in gene therapy to introduce a foreign gene into endothelial cells to correct or prevent vascular disorders. 15. The method as claimed in claim 14 wherein the vascular disorders are hypertension, atherosclerosis, arthritis, restenosis, and cancer. 16. The method as claimed in claim 14 or 15 wherein the foreign gene encodes a therapeutic agent preferably an anticoagulant, vasodilator or angiogenic factor. 17. A method of using the transcriptional regulatory element as claim 1 in gene therapy to introduce a foreign gene into endothelial cells to treat systemic or inherited disorders. 18. An isolated transcriptional regulatory element characterized by directing expression of a gene in embryonic and adult mice specifically in cells of the endothelial lineage. 19. A method of using the transcriptional regulatory element as claimed in claim 18 to express a gene in mammalian cells of the endothelial lineage. 20. A method as claimed in claim 19 wherein the transcriptional regulatory element is used to express a gene in an embryonic or adult mouse.

Inventors: BREITMAN MARTIN L, DUMONT DANIEL, GRADWOHL GERARD G, BREITMAN, MARTIN, L., DUMONT, DANIEL, GRADWOHL, GERARD, G.
Applicants: BREITMAN MARTIN L, DUMONT DANIEL, GRADWOHL GERARD G, MOUNT SINAI HOSPITAL CORP, MOUNT SINAI HOSPITAL CORPORATION
Application year: 1993
Main classification: C12N15
IPC codes: A01K67, A61K31, A61K48, A61P9, A61P35, A61P43, C07H21, C12N5, C12N9, C12N15, C12R1