WO1998004288A1 - Bovine leptin protein, nucleic acid sequences coding therefor and uses thereof - Google Patents
Bovine leptin protein, nucleic acid sequences coding therefor and uses thereof Download PDFInfo
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- WO1998004288A1 WO1998004288A1 PCT/US1997/012532 US9712532W WO9804288A1 WO 1998004288 A1 WO1998004288 A1 WO 1998004288A1 US 9712532 W US9712532 W US 9712532W WO 9804288 A1 WO9804288 A1 WO 9804288A1
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- leptin
- polypeptide
- dna
- adipocyte
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- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07K—PEPTIDES
- C07K14/00—Peptides having more than 20 amino acids; Gastrins; Somatostatins; Melanotropins; Derivatives thereof
- C07K14/435—Peptides having more than 20 amino acids; Gastrins; Somatostatins; Melanotropins; Derivatives thereof from animals; from humans
- C07K14/575—Hormones
- C07K14/5759—Products of obesity genes, e.g. leptin, obese (OB), tub, fat
Definitions
- This invention relates to the regulation of energy intake and metabolism in
- leptin which is secreted by adipocytes or other cell types and which influences energy intake and metabolism, fat deposition, and weight gain in bovine.
- this invention relates to the nucleotide sequences
- bovine leptin polypeptide encoding the bovine leptin polypeptide, the antibodies directed against the bovine leptin polypeptide, and methods to determine susceptibility to fat deposition, alter energy intake, and minimize excessive fat deposition in bovine.
- Proteins from genes expressed only (or predominantly) in adipose tissue and for which the level of expression can be related to fat deposition serve as prime targets for approaches directed toward prediction of fat accretion potential and the control of fat deposition.
- a mammalian adipocyte-specific polypeptide termed pl54
- Leptin the protein produced by the leptin (ob) gene, is possibly related to fat
- leptin is expressed specifically in the terminally differentiated adipocyte (Maffei et al. , 1995, Proc. Natl. Acad. Sci. 92:6957; Leroy et al. , 1996, J. Biol. Chem. 271(5):2365). Additionally, leptin is a regulator of feed intake (Pellymounter et al., 1995, Sci. 269:540; Halaas et al. , 1995, Sci. 269:543; Campfield et al. , 1995, Sci. 269:546).
- active purified bovine protein i.e. , leptin
- the present invention provides gene sequences, peptides, antibodies, and methods
- this invention is directed to a bovine adipocyte polypeptide, the
- bovine leptin protein substantially free of other bovine proteins, or a functional derivative thereof.
- the present invention includes a bovine adipocyte polypeptide consisting essentially of at least about 8 amino acids of the amino acid sequence depicted in Figures 1 and 3-5, or a functional derivative thereof.
- the present invention is also directed to a single or double stranded DNA
- the DNA molecule is preferably a single or double stranded DNA molecule having a nucleotide sequence
- RNA molecule is preferably an mRNA sequence
- bovine adipocyte polypeptide encoding the above bovine adipocyte polypeptide, or a functional derivative thereof.
- a DNA molecule as described above which is cDNA or genomic DNA, preferably in the form of an expressible vehicle or plasmid.
- the present invention is also directed to hosts transformed or transfected with the above DNA molecules, including a prokaryotic host, preferably a bacterium, a eukaryotic host such as a yeast cell, or a mammalian cell.
- a prokaryotic host preferably a bacterium, a eukaryotic host such as a yeast cell, or a mammalian cell.
- the present invention also provides a process for preparing a bovine adipocyte polypeptide or functional derivative as described above, the process comprising the steps of: (a) culturing a host capable of expressing the polypeptide under culture conditions; (b) expressing the polypeptide; and (c) recovering the polypeptide from the culture.
- Also included in the present invention is a method for detecting the presence of a
- nucleic acid molecule having the sequence of the DNA molecule described above, or a complementary sequence, in a nucleic acid-containing sample, the method comprising: (a) contacting the sample with an oligonucleotide probe complementary to the sequence of
- the above method may additionally comprise before step (a): (c) selectively amplifying the number of copies of the nucleic acid sequence.
- Another embodiment of this invention is an antibody specific for an epitope of the bovine adipocyte polypeptide, or functional derivative, either polyclonal or monoclonal. Also intended is a method for detecting the presence or measuring the quantity of the bovine adipocyte polypeptide, or functional derivative, either polyclonal or monoclonal. Also intended is a method for detecting the presence or measuring the quantity of the bovine adipocyte polypeptide, or functional derivative, either polyclonal or monoclonal. Also intended is a method for detecting the presence or measuring the quantity of the bovine adipocyte polypeptide, or functional derivative, either polyclonal or monoclonal. Also intended is a method for detecting the presence or measuring the quantity of the bovine adipocyte polypeptide, or functional derivative, either polyclonal or monoclonal. Also intended is a method for detecting the presence or measuring the quantity of the bovine adipocyte polypeptide, or functional derivative, either polyclonal or monoclonal. Also intended is
- bovine adipocyte polypeptide leptin in a biological sample comprising contacting the sample with the above antibody and detecting the binding of the antibody to an antigen in the sample, or measuring the quantity of antibody bound.
- the present invention includes methods for determining the susceptibility of cattle to fat deposition which comprises removing a biological sample from a subject and measuring therein the amount of the polypeptide or mRNA coding therefor, where the amount of the polypeptide or mRNA is related to susceptibility.
- methods for determining the susceptibility of a subject to fat deposition which comprises removing a biological sample, extracting the DNA, digesting the DNA with restriction endonucleases, probing the sample with an oligonucleotide probe, separating the resulting fragments by gel electrophoresis, and relating the number of
- bands generated by restriction enzyme digestion to fat deposition (i.e. ,
- Another method provided herein is for evaluating the efficacy of a drug (or other agent) directed to the regulation of fat deposition and feed intake which comprises contacting the drug being tested with an adipocyte culture in vitro and measuring the
- the efficacy of the drug being related to changing the production of the polypeptide or mRNA.
- FIG. 1 depicts the bovine leptin cDNA nucleotide sequence (top) and predicted amino acid sequence (bottom) for the coding region minus the secretory signal.
- FIG. 2A shows a comparison of the bovine leptin cDNA nucleotide sequence
- FIG. 2B shows a comparison of the bovine leptin cDNA nucleotide sequence with the murine nucleotide sequence.
- FIG. 3A shows a comparison of the predicted bovine leptin amino acid sequence with the human leptin amino acid sequence.
- FIG. 3B shows a comparison of the predicted bovine leptin amino acid sequence with the murine leptin amino acid sequence.
- FIG. 4 depicts a portion of the actual bovine leptin amino acid sequence which is
- FIG. 5 A shows a comparison of the actual bovine leptin amino acid sequence with the human leptin amino acid sequence.
- FIG. 5B shows a comparison of the actual bovine leptin amino acid sequence with the murine leptin amino acid sequence.
- FIG. 6 shows that a band of 449 base pairs was obtained from a PCR- amplified
- FIG. 7 depicts the Northern blot analysis of bovine leptin mRNA.
- the present invention is directed to DNA and RNA molecules that encode a bovine adipocyte polypeptide termed "leptin", or a functional derivative thereof, and the bovine leptin protein itself, or a functional derivative thereof.
- the bovine leptin protein is useful for the regulation of feed intake, energy metabolism, and fat deposition in cattle. Such objectives can be achieved by administering recombinant or purified leptin, altering the expression of the bovine leptin gene or administering an antibody directed against the bovine leptin protein to achieve neutralization, depending upon the desired result.
- the bovine leptin DNA, RNA, and protein, or functional derivatives thereof, and antibodies specific for the protein are used in assays to predict the potential for fat deposition in cattle. These molecules can also be utilized in the development of commercially valuable
- the present invention provides a bovine adipocyte polypeptide termed "leptin" .
- the term "polypeptide” as used herein is intended to include not only the bovine leptin protein, and functional derivatives thereof, but also amino acid sequences having additional components, e.g. , amino acid sequences having additional
- components such as a sugar, as in a glycopeptide, or other modified protein structures
- polypeptide of this invention has an amino acid sequence as depicted in Figures 1 and 3-5. Also intended within the scope of the present invention is any peptide having at least about 8 amino acids present in the above-mentioned sequence. Sequences of this length are useful as antigens and for making immunogenic conjugates with carriers for the production of antibodies specific for various epitopes of the entire protein. Such peptides are also useful in screening such antibodies and in the methods of the present invention directed to detection of the leptin protein in biological samples. It is well-known in the art that peptides of about 8 amino acids are useful in generation of antibodies to larger proteins of biological interest.
- polypeptide of this invention is sufficiently large to comprise an antigenically distinct determinant, or epitope, which can be used as an immunogen to produce
- polypeptide of this invention may also exist covalently or noncovalently bound to another molecule.
- it may be fused (i.e. , a fusion protein) to one or more other polypeptides via one or more peptide bonds.
- a fusion protein i.e. , a fusion protein
- One embodiment includes the polypeptide substantially free of other bovine peptides.
- the polypeptide of the present invention may be biochemically or immunochemically purified from cells, tissues, or a biological fluid. Alternatively, the
- polypeptide can be produced by recombinant means in a prokaryotic or eukaryotic host
- the gene for the bovine adipocyte polypeptide of interest can be cloned, the polypeptide can be expressed in a prokaryotic or eukaryotic organism, if desired. Methods are also well known for the synthesis of polypeptides of a desired sequence on solid phase supports and their subsequent separation from the support. Alternatively, the protein can be purified
- tissue or fluids of the bovine in which it naturally occurs so that it is purified away from at least 90 percent (on a weight basis), and from even at least 99 percent if desired, of other bovine polypeptides and is therefore substantially free of them. That can be achieved by subjecting the tissue or fluids to standard protein purification techniques such
- the purification from such tissue or fluids can be achieved by a combination of standard methods, such as ammonium sulfate precipitation, molecular sieve chromatography, and ion exchange chromatography.
- analog or “chemical derivative” of the bovine adipocyte polypeptide that retains at least a portion of the function of the bovine adipocyte polypeptide which permits its utility
- a “fragment” of the bovine adipocyte polypeptide as used herein refers to any subset of the molecule, that is, a shorter peptide.
- a "variant" of the bovine adipocyte polypeptide as used herein refers to a molecule substantially similar to either the entire peptide or a fragment thereof. Variant peptides may be conveniently prepared by direct chemical synthesis of the variant peptide,
- amino acid sequence variants of the peptide can be prepared by mutations in the DNA which encodes the synthesized peptide (again using methods well-known in the art). Such variants include, for example, deletions from, or insertions or substitutions of, residues within the amino acid sequence. Any combination of deletion, insertion, and substitution may also be made to arrive at the final construct, provided that the final construct possesses the desired activity.
- the mutations that will be made in the DNA encoding the variant peptide must not alter the reading frame and preferably will not create complementary regions that
- an "analog" of the bovine adipocyte polypeptide as used herein refers to a non-natural molecule substantially similar to either the entire molecule or a fragment
- a "chemical derivative" of the bovine adipocyte polypeptide or peptide as used herein contains additional chemical moieties not normally a part of the polypeptide. Covalent modifications are included within the scope of this invention.
- the polypeptide of the present invention is encoded by a nucleic acid molecule, one strand of which has the nucleotide sequence shown in Figures 1 and 2.
- the present invention is directed to a DNA sequence encoding the polypeptide, or a functional derivative thereof, substantially free of other bovine DNA sequences.
- DNA may be single-stranded (i.e. , sense, antisense or cDNA sequence) or double- stranded.
- the DNA sequence should preferably have about 20 or more nucleotides to allow hybridization to another polynucleotide. In order to achieve higher specificity of hybridization, characterized by the absence of hybridization to sequences other than those encoding the
- polypeptide or a functional derivative thereof, a length of at least about 50 nucleotides is preferred.
- the present invention is also directed to an RNA molecule comprising a mRNA sequence encoding the polypeptide of this invention, or a functional derivative thereof.
- the present invention is further directed to the above DNA molecules which are functional in recombinant expression systems utilizing as hosts transfected or transformed
- Such hosts may be prokaryotic or eukaryotic.
- the DNA can be incorporated into the host organism by
- this invention provides methods for the expression of the nucleic acid sequence encoding the bovine adipocyte polypeptide molecule.
- the genetic sequences and oligonucleotides of the invention allow the identification and cloning of additional, yet undiscovered adipocyte polypeptides having sequence homology to the bovine adipocyte polypeptide described herein.
- the recombinant DNA molecules of the present invention can be produced through any of a variety of means, such as, for example, DNA or RNA synthesis, or more preferably, by application of recombinant DNA techniques. Techniques for synthesizing such molecules are disclosed by, for example, Wu, R. , et al. , Prog. Nucl. Acid. Res. Molec. Biol. 21 : 101-141 (1978), which is incorporated herein by reference. Procedures for constructing recombinant molecules in accordance with the above-described method are disclosed by Sambrook et al. Molecular Cloning: A Laboratory Manual, Second Edition, Cold Spring Harbor Press, Cold Spring Harbor, N.Y. (1989), which is herein
- Oligonucleotides representing a portion of the bovine adipocyte polypeptide of this invention are useful for screening for the presence of genes encoding such proteins and
- a suitable oligonucleotide, or set of oligonucleotides, which is capable of encoding a fragment of the bovine adipocyte polypeptide gene of this invention (or which is complementary to such an oligonucleotide, or set of oligonucleotides) is identified,
- a cDNA preparation derived from cells which are capable of expressing the bovine adipocyte polypeptide gene.
- DNA synthesis may be achieved through the use of automated synthesizers. Techniques of nucleic acid hybridization are disclosed by Sambrook et al. (supra).
- a library of expression vectors is prepared by cloning DNA or, more preferably, cDNA (from a cell capable of expressing the bovine adipocyte polypeptide)
- the library is then screened for members capable of expressing a protein which binds to anti-bovine adipocyte polypeptide antibody, and which has a nucleotide sequence that is capable of encoding polypeptides that have the same amino acid sequence as the bovine adipocyte polypeptide of this invention, or
- DNA, or more preferably cDNA is extracted and purified from a cell which is capable of expressing the bovine adipocyte polypeptide protein.
- the purified cDNA is fragmentized (by shearing, endonuclease digestion, etc.) to produce a pool of DNA or cDNA fragments.
- DNA or cDNA fragments from this pool are then cloned into an expression vector in order to produce a library of expression
- vectors whose members each contain a unique cloned DNA or cDNA fragment.
- An "expression vector” is a vector which (due to the presence of appropriate transcriptional and/or translational control sequences) is capable of expressing a DNA (or
- Expression vectors of the present invention may be either procaryotic or eukaryotic.
- suitable prokaryotic expression vectors include pASK75 (Biometra) or pET 21a-d (Novagen).
- suitable eukaryotic expression vectors include pcDNA3 or pRc/RSV (In Vitrogen, Inc.).
- a DNA sequence encoding the bovine adipocyte polypeptide of the present invention, or its functional derivative, may be recombined with vector DNA in accordance with conventional techniques such as those disclosed by Sambrook, et al. (supra).
- a nucleic acid molecule, such as DNA, is said to be "capable of expressing" a polypeptide if it contains nucleotide sequences which contain transcriptional and translational regulatory information and such sequences are “operably linked” to nucleotide sequences which encode the polypeptide.
- An operable linkage is a linkage in which the regulatory DNA sequences and the DNA sequence sought to be expressed are
- a promoter region which, in prokaryotes, contains both the promoter (which directs the initiation of RNA transcription) as well as the DNA sequences which, when transcribed into RNA, will signal the initiation of protein synthesis.
- a promoter is a double-stranded DNA or RNA
- the promoter sequences of the present invention may be either prokaryotic, eukaryotic or viral. Strong promoters are, however, preferred. Suitable promoters are repressible, or more preferably, constitutive.
- suitable prokaryotic promoters include the tetracycline (Tet A) promoter for pASK75 and T71ac for pET21.
- suitable eukaryotic promoters include alpha actin or beta actin.
- suitable viral promoters include Rous sarcoma or cytomegala.
- the present invention is also directed to an antibody specific for an epitope of the bovine adipocyte polypeptide of the present invention, and the use of such antibody to detect the presence of, or measure the quantity or concentration of the polypeptide, or a functional derivative thereof, in a cell, a cell or tissue extract, or a biological fluid.
- epitope refers to that portion of any molecule capable of being bound by an antibody which can also be recognized by that antibody.
- antigenic determinants usually consist of chemically active surface groupings of molecules such as amino acids or sugar side chains and have specific three dimensional structural characteristics as well as specific charge characteristics.
- An antibody is said to be “capable of binding” a molecule if it is capable of specifically reacting with the molecule to thereby bind the molecule to the antibody.
- the bovine adipocyte polypeptide of the present invention or a functional derivative thereof, preferably having at least about 8 amino acids is used as an antigen for induction of a polyclonal antibody or monoclonal antibody (mAb).
- an "antigen" is a molecule or a portion of a molecule capable of being bound by an antibody which is additionally capable of inducing an animal to produce antibody capable of binding to an epitope of that antigen.
- An antigen may have one, or more than one epitope.
- the specific reaction referred to above is meant to indicate that the antigen will react, in a highly selective manner, with its corresponding antibody and not with the multitude of other antibodies which may be evoked by other antigens.
- antibody is meant to include polyclonal antibodies, monoclonal antibodies (mAbs), and chimeric antibodies.
- Polyclonal antibodies are heterogeneous populations of antibody molecules derived from the sera of animals immunized with an antigen.
- Monoclonal antibodies are a substantially homogeneous population of antibodies to specific antigenic epitopes.
- MAbs may be obtained by methods known to those skilled in the art. (See, for example Kohler and Milstein, Nature 256:495-497 (1975) and U.S. Pat. No. 4,376, 110; de St. Groth, S. F. et al.. J. Immunol. Methods, 35: 1-21 (1980); and Hartlow, E. et al., Antibodies: A Laboratory Manual, Cold Spring Harbor Laboratory Press, Cold Spring Harbor, N.Y. , 1988).
- Chimeric antibodies are molecules different portions of which are derived from
- antibody is also meant to include both intact molecules as well as fragments thereof, such as, for example, Fab and F(ab')2, which are capable of binding antigen.
- Fab and F(ab')2 fragments lack the Fc fragment of intact antibody, clear more rapidly from the circulation, and may have less non-specific tissue binding than an intact
- Such fragments are typically produced by proteolytic cleavage, using enzymes such as papain (to produce Fab fragments) or pepsin (to produce F(ab')2 fragments).
- the reaction of the antibodies and the polypeptides of the present invention are detected by immunoassay methods well known in the art (See, for example, Hartlow et al. supra).
- the antibodies, or fragments of antibodies, useful in the present invention are detected by immunoassay methods well known in the art (See, for example, Hartlow et al. supra).
- the antibodies (or fragments thereof) useful in the present invention may be employed histologically, as in immunofluorescence or immunoelectron microscopy, for in
- Such assays for the bovine adipocyte polypeptide of the present invention typically comprise incubating a biological sample, such as a biological fluid, a tissue extract, freshly harvested or cultured cells containing adipogenic cells or adipocytes, in the presence of a detectably labeled antibody capable of identifying the bovine adipocyte polypeptide, and detecting the antibody by any of a number of techniques well-known in the art, such as enzyme immunoassays (EIA or ELISA) or radioimmunoassays (RIA).
- a biological sample such as a biological fluid, a tissue extract, freshly harvested or cultured cells containing adipogenic cells or adipocytes
- a detectably labeled antibody capable of identifying the bovine adipocyte polypeptide
- the antibody molecules of the present invention may also be adapted for utilization in an immunometric assay, also known as a "two-site” or “sandwich” assay.
- an immunometric assay also known as a "two-site” or “sandwich” assay.
- a quantity of unlabeled antibody (or fragment of antibody) is bound to a solid support (i.e. , any support capable of binding antigen or antibodies) and a quantity of detectably labeled soluble antibody is added to permit detection and/or quantification of the ternary complex formed between solid-phase antibody, antigen, and
- the binding activity of a given lot of antibody to the bovine adipocyte polypeptide may be determined according to well known methods. Those skilled in the art will be
- Antibodies can be used in an immunoaffinity column to purify the binding
- adipocyte polypeptide of the invention by a one step procedure, using methods known in the art.
- cattle that are susceptible to fat deposition is provided. According to the present invention, cattle that are susceptible to fat deposition is provided.
- a typical regimen for treating cattle with a propensity for fat deposition comprises administration of an effective amount of the bovine adipocyte polypeptide administered over a period of time.
- the bovine adipocyte polypeptide of the present invention may be administered by any means that achieves its intended purpose, preferably to alter feed intake or limit fat deposition in a subject.
- administration may be by various parenteral routes including, but not limited to, subcutaneous, intravenous, intradermal, intramuscular, and intraperitoneal routes.
- administration may be by the oral route which may be accomplished by the use of genetically-altered feedstuffs, in which the bovine leptin gene has been inserted and expressed.
- Parenteral administration can be by bolus injection or by gradual perfusion over time such as by implant of osmotic
- Preparations for parenteral administration include sterile aqueous or non-aqueous solutions, suspensions, and emulsions, which may contain auxiliary agents or excipients which are known in the art.
- Pharmaceutical compositions such as tablets and capsules can also be prepared according to routine methods.
- bovine adipocyte polypeptide of the present invention administered may be dependent upon the age, sex, health, and weight of the recipient, kind of concurrent treatment, if any, frequency of treatment, and the nature of the effect desired. The most preferred dosage will be tailored to the individual subject, as is understood and determinable by one of skill in the art.
- the total dose required for each treatment may be administered by multiple doses or in a single dose.
- the bovine adipocyte polypeptide of the present invention may be administered alone or in conjunction with other therapeutics directed toward the regulation of feed intake and/or fat deposition.
- the concentration of the bovine adipocyte polypeptide or mRNA of this invention is measured in a cell preparation, tissue extract or biological fluid of a subject as a means for determining the susceptibility or the propensity of the
- the susceptibility of the subject to fat deposition is related to
- bovine adipocyte polypeptide the level of the bovine adipocyte polypeptide, or its mRNA. Additionally, restriction fragment length polymorphisms in the bovine adipocyte gene will be used to predict fat deposition potential.
- Another embodiment of the invention is evaluating the efficacy of a drug, or other agent, directed to the increase or decrease of feed intake by measuring the ability of the drug or agent to stimulate or suppress the production of the bovine adipocyte polypeptide
- a cell or cell line capable of producing such polypeptides or mRNAs by a cell or cell line capable of producing such polypeptides or mRNAs.
- Preferred cells are cells of an adipogenic cell line.
- the antibodies, cDNA probe or riboprobe of the present invention are useful in the method for evaluating these drugs or other agents in that they can be employed to determine the amount of the bovine adipocyte polypeptide or mRNAs using one of the above-mentioned immunoassays.
- An additional embodiment of the present invention is directed to assays for measuring the susceptibility of cattle to fat deposition based on measuring in a tissue or fluid from the subject the amount of the mRNA sequences present that encode the bovine adipocyte polypeptide, or a functional derivative thereof, preferably using an RNA or DNA hybridization assay.
- the susceptibility to fat deposition is related to the amount of such mRNA sequences present.
- the source of the mRNA sequences is preferably the adipogenic cells of cattle.
- the preferred technique for measuring the amount of mRNA is a hybridization assay using RNA (e.g. , ribonuclease protection assay) or DNA (e.g.
- Nucleic acid detection assays can be predicated on any characteristic of the nucleic acid molecule, such as its size, sequence, susceptibility to digestion by restriction endonucleases, etc.
- the sensitivity of such assays may be
- assay sensitivity can be increased through the use of detectably labeled reagents.
- a wide variety of such labels have been used for this purpose.
- Kourilsky et al. U.S. Pat. No. 4,581 ,333
- Radioisotopic labels are disclosed by Falkow et al. (U.S. Pat. No. 4,358,535), and by Berninger (U.S. Pat. No. 4,446,237).
- Fluorescent labels Albarella et al. , EP 144914
- chemical labels Sheldon III et al. , U.S. Pat. No.
- One method for overcoming the sensitivity limitation of nucleic acid concentration is to selectively amplify the nucleic acid whose detection is desired prior to performing the assay.
- Recombinant DNA methodologies capable of amplifying purified nucleic acid fragments have long been recognized. Typically, such methodologies involve the introduction of the nucleic acid fragment into a DNA or RNA vector, the clonal
- the polymerase chain reaction provides a method for selectively increasing
- the method can be used to amplify either single- or double-stranded DNA.
- the essence of the method involves the use of two oligonucleotide probes to serve as primers for the template-dependent, polymerase mediated replication of a desired nucleic acid molecule.
- the single-stranded bovine cDNA pool was used as a template to amplify bovine leptin cDNA in a PCR reaction with synthetic DNA primers based on the published mouse leptin cDNA sequence.
- Two pairs of oligonucleotide degenerate primers specific for the human and murine leptin gene were designed and synthesized (DNA International, Lake Oswego, OR).
- the primers were designed to amplify the coding region of the bovine leptin gene, excluding the secretory signal at the 5'-terminal of the coding region).
- the forward primer has a sequence of 5'-GGA TCC GGT CTC AGG CCG TGC CYA
- PCR was performed using the following conditions: IX PCR buffer, 1.5 mM MgCl2, 1 ⁇ M primers, 0.2 mM dNTPs and 5 units
- lane 1 of Figure 6 contains the 449 base pair bovine leptin cDNA
- lane 2 contains the pASK75 vector DNA
- lane 3 contains standard 100 base pair ladder.
- the size of the PCR product was consistent with the predicted size of the coding region of the bovine leptin
- This PCR product was verified in a secondary PCR procedure.
- This vector originally derived from pASK60, carries the promoter/ operator region from the TetA resistance gene, and allows precise insertion of a gene and direct expression of a structural gene with the OmpA signal sequence and a
- Strep-tag polypeptide which is designed for affinity purification of the recombinant protein.
- the vector pASK75 plasmid was cut with the same enzymes and then digested with bovine intestinal alkaline phosphatase (CIAP, Gibco BRL, ) to remove the 5 '-phosphate group. This step prevents vector-vector ligations during the ligation reaction. After confirming by gel electrophoresis that the PCR product and vector were digested appropriately, the ligation was accomplished using T4 DNA ligase (Gibco BRL) with incubation at 14 C for 20 h.
- UCP bovine intestinal alkaline phosphatase
- the recombinant bovine leptin DNA product was then transformed into an E. coli strain
- the E. coli were grown in culture, and the recombinant plasmid DNA induced to express the bovine leptin gene by adding anhydrotetracycline at a concentration below that required for antibiotic activity.
- the bovine leptin protein was then purified by either SDS-PAGE or Strep-Tag affinity chromatography.
- the recombinant plasmid DNA was also purified using a plasmid miniprep kit (Promega). The purified plasmid containing the bovine leptin insert was submitted to National Bioscience, Inc. for DNA
- ATCC American Type Culture Collection
- Sequencing of the insert DNA was performed by a commercial laboratory (National Bioscience, Inc.) using the standard Sanger's dideoxy- nucleotide method. Briefly, the PCR product containing the 449 bp band was separated on a 1 % low-melting-agarose gel. The 449 bp band was cut from the gel, further purified using a Genecleaning kit (BiolOl , Inc, Vista, CA), and submitted for sequencing. The sequences were then compared with the Genebank and other databses using the GCG software. The sequence data confirm that the 449 bp product from two independent
- the actual amino acid sequence i.e. , the N-terminal sequence (FIG. 4)
- the bovine leptin cDNA was used as a probe for detection of the full length mRNA on a Northern blot containing bovine adipose tissue poly A -I- mRNA and ob/ob mouse adipose total RNA (FIG. 7).
- the RNA samples were separated on a 1 % formaldehyde agarose gel and then transferred to a nylon membrane (Zeta-probe, Biorad) by a capillary transfer method in 10X SSC (1.5M NaCl, 0.15 M Sodium Citrate, pH 7.0).
- the blot was hybridized with an alpha-[ 32 PJ dCTP labeled bovine leptin cDNA in hybridization solution (Gibco BRL; 0.9 M NaCl, 0.09 M Sodium Citrate (pH 7.0), 0.01
- bovine leptin mRNA (approximately 3,090 bp) was clearly evident in the bovine adipose tissue and an approximate 3,240 bp leptin mRNA was detected in the ob/ob mouse adipose tissue.
- lanes 6-8 contain the ob/ob mouse adipose total RNA and lane 10 contains the bovine adipose poly A + mRNA.
- RNAse protection assay was established to quantify bovine leptin mRNA in adipose tissue. Briefly, a T7 promoter DNA sequence was added to the antisense leptin ob primer via PCR with the sense primer as described in Example I. This modified antisense primer produced a 478 bp fragment containing the T7 promoter.
- RPA RNAse protection assay
- riboprobe was then generated by in vitro transcription with alpha-[ 32 P]-UTP and the 478 bp PCR fragment.
- the RPA was performed using a commercially available kit (RPA II, Ambion, Inc.). Hybridization was done with 50,000 cpm of the bovine leptin riboprobe and 10 ⁇ g of adipose total RNA for 20 h at 42-45C. Single-stranded RNA was then digested by a 1 :50 dilution of RNAse Tl for 30 min at 37C. After ethanol precipitation, the protected fragment was separated in a 5 % poly aery lamide gel with 8M urea. The gel was then dried and exposed to X-ray film and a single 449 bp fragment was protected. Beta- actin was used as an internal control for standardization of the RPA results.
- the bovine leptin cDNA was also used to screen a bovine genomic DNA library.
- bovine genomic library (Holstein dairy cow) was purchased from a commercial source (Stratagene, Inc.). The library, containing 2 X 10 6 plaque forming
- the polypeptide sequence encoded by the bovine leptin cDNA was purified by preparative SDS-polyacrylamide gel electrophoresis and then the recombinant protein band was electroeluted from the gel.
- the purified protein will be used for production of antibodies and development of ELISA and other assay methodologies.
- Polyclonal and/or monoclonal antibodies are produced with the recombinant bovine leptin protein.
- the techniques used for producing, screening, detecting, and/or quantifying antibodies or leptin are discussed extensively in "Antibodies: a laboratory manual” (Harlow et al. , 1988, Cold Spring Harbor laboratory). All media or medium
- mouse or cell strains e.g. BALB/C mouse, sp2/0 myeloma cells, JA744A.1 macrophages etc. are commercially available.
- Purified bovine leptin protein is injected into rabbits for production of polyclonal antibodies. Specifically, each rabbit receives repeated subcutaneous injections with antigen in Freund's complete adjuvant followed by at least 1 booster injection of about
- rabbit serum is harvested as the polyclonal antiserum for bovine leptin.
- Purified bovine leptin protein is injected into BALB/C mice for production of
- each mouse is injected with about 50 ⁇ g bovine leptin protein with Ribi's S-TDCM adjuvants (RIBI ImmunoChem Research, Inc. , Hamilton, Montana).
- Ribi's S-TDCM adjuvants RIBI ImmunoChem Research, Inc. , Hamilton, Montana.
- the number of injections depends on the titer of the antibody in the serum of immunized mice as determined by ELISA using bovine leptin as the antigen.
- the spleens In the course of producing monoclonal antibodies against bovine leptin protein, the spleens
- Hybridoma cells will be made by fusing the spleenocytes with sp2/0 myeloma cells (treated with 8-Azaguanine containing medium) in the presence of 50% PEG-1500. Hybridoma cells are incubated in selection
- HAT hypoxanthine, aminopterin, and thymidine
- positive clones uses the recombinant bovine leptin as antigen in ELISA or Western blot methodology. Positive clones that produce strong anti-bovine-leptin antibody is characterized for specificity, subtype, affinity, binding sites, etc.
- the positive clones are cultured in large scale and antibody purified from the culture supernatant, or injected into the intraperitoneal cavity of BALB/C mice for production of ascites.
- the latter procedure requires about 1-2x10° hybridoma cells per mouse, and usually takes about 7-14 days.
- Large quantities of antibody is purified from ascites by techniques such as ammonium sulphate precipitation and ion exchange chromatography (e.g. DEAE-Trisacryl M).
Abstract
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Application Number | Priority Date | Filing Date | Title |
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AU36032/97A AU740739B2 (en) | 1996-07-31 | 1997-07-17 | Bovine leptin protein, nucleic acid sequences coding therefor and uses thereof |
CA002262478A CA2262478A1 (en) | 1996-07-31 | 1997-07-17 | Bovine leptin protein, nucleic acid sequences coding therefor and uses thereof |
EP97932626A EP0964701A4 (en) | 1996-07-31 | 1997-07-17 | Bovine leptin protein, nucleic acid sequences coding therefor and uses thereof |
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US08/688,908 US6297027B1 (en) | 1996-07-31 | 1996-07-31 | Bovine leptin protein, nucleic acid sequences coding therefor and uses thereof |
US08/688,908 | 1996-07-31 |
Publications (1)
Publication Number | Publication Date |
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WO1998004288A1 true WO1998004288A1 (en) | 1998-02-05 |
Family
ID=24766275
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
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PCT/US1997/012532 WO1998004288A1 (en) | 1996-07-31 | 1997-07-17 | Bovine leptin protein, nucleic acid sequences coding therefor and uses thereof |
Country Status (5)
Country | Link |
---|---|
US (1) | US6297027B1 (en) |
EP (1) | EP0964701A4 (en) |
AU (1) | AU740739B2 (en) |
CA (1) | CA2262478A1 (en) |
WO (1) | WO1998004288A1 (en) |
Families Citing this family (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20020110857A1 (en) * | 1996-07-31 | 2002-08-15 | Spurlock Michael E. | Bovine leptin protein, antisense and antibody |
CA2387003A1 (en) * | 2002-05-21 | 2003-11-21 | 984012 Alberta Ltd. | Method for improving efficiencies in livestock production |
EP2390352A1 (en) | 2003-03-18 | 2011-11-30 | Quantum Genetics Ireland Limited | Systems and methods for improving protein and milk production of dairy herds |
US7320868B2 (en) * | 2004-03-19 | 2008-01-22 | Arieh Gertler | Leptin binding domain compositions and methods thereto |
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US4237224A (en) | 1974-11-04 | 1980-12-02 | Board Of Trustees Of The Leland Stanford Jr. University | Process for producing biologically functional molecular chimeras |
FR2422956A1 (en) | 1978-04-13 | 1979-11-09 | Pasteur Institut | METHOD OF DETECTION AND CHARACTERIZATION OF A NUCLEIC ACID OR OF A SEQUENCE OF THE SAME, AND ENZYMATIC REAGENT FOR THE IMPLEMENTATION OF THIS PROCESS |
DE3028001A1 (en) | 1980-07-24 | 1982-02-18 | Dr. Karl Thomae Gmbh, 7950 Biberach | NEW 5,10-DIHYDRO-11H-DIBENZO (B, E) (1,4) DIAZEPINE-11-ONE SUBSTITUTED, PRODUCTION METHOD AND PRODUCTS CONTAINING THIS COMPOUND |
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-
1996
- 1996-07-31 US US08/688,908 patent/US6297027B1/en not_active Expired - Fee Related
-
1997
- 1997-07-17 CA CA002262478A patent/CA2262478A1/en not_active Abandoned
- 1997-07-17 EP EP97932626A patent/EP0964701A4/en not_active Withdrawn
- 1997-07-17 AU AU36032/97A patent/AU740739B2/en not_active Ceased
- 1997-07-17 WO PCT/US1997/012532 patent/WO1998004288A1/en not_active Application Discontinuation
Non-Patent Citations (3)
Title |
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MAMMALIAN GENOME, Vol. 7, 1996, STONE et al., "The Bovine Homolog of the Obese Gene Maps to Chromosome 4", pages 399-400. * |
NATURE, Vol. 372, 1 December 1994, ZHANG et al., "Positional Cloning of the Mouse Obese Gene and its Human Homologue", pages 425-432. * |
See also references of EP0964701A4 * |
Also Published As
Publication number | Publication date |
---|---|
CA2262478A1 (en) | 1998-02-05 |
AU3603297A (en) | 1998-02-20 |
EP0964701A1 (en) | 1999-12-22 |
US6297027B1 (en) | 2001-10-02 |
EP0964701A4 (en) | 2004-03-17 |
AU740739B2 (en) | 2001-11-15 |
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