Methods to identify growth differentiation factor (GDF) receptors

Abstract

The present invention provides receptors for the growth differentiation factor (GDF) family of growth factors and methods of identifying such receptors. Also included are methods of identifying antibodies which bind to the receptors, peptide fragments of the receptor which inhibit GDF binding, GDF receptor-binding agents capable of blocking GDF binding to the receptor. The receptors of the invention allow the identification of antagonists or agonists useful for agricultural and human therapeutic purposes.

What is claimed is:  
     
         1 . A recombinant cell line that expresses growth differentiation factor-8 (GDF-8) or growth differentiation factor-11 (GDF-11) receptor polypeptide.  
     
     
         2 . The cell line of  claim 1 , wherein the cell is selected from the group of species consisting of avian, bovine, ovine, piscine, murine, human and porcine.  
     
     
         3 . An antibody which specifically binds to growth differentiation factor-8 (GDF-8) receptor polypeptide or fragments thereof.  
     
     
         4 . The antibody of  claim 7 , wherein the antibody is a monoclonal antibody.  
     
     
         5 . An antibody which specifically binds to growth differentiation factor-11 (GDF-11) receptor polypeptide or fragments thereof.  
     
     
         6 . The antibody of  claim 7 , wherein the antibody is a monoclonal antibody.  
     
     
         7 . An isolated polynucleotide which encodes growth differentiation factor-8 (GDF-8) receptor.  
     
     
         8 . An isolated polynucleotide which encodes growth differentiation factor-11 (GDF-11) receptor.  
     
     
         9 . An expression vector containing in operable linkage the polynucleotide as in  claim 7  or  8 .  
     
     
         10 . A host cell containing the vector of  claim 9 .  
     
     
         11 . A substantially purified peptide fragment of GDF-8 receptor, wherein the peptide inhibits GDF-8 binding to GDF-8 receptor.  
     
     
         12 . A substantially purified peptide fragment of GDF-11, wherein the peptide inhibits GDF-11 binding to GDF-11 receptor.  
     
     
         13 . A substantially purified GDF-8-binding agent, wherein the binding agent inhibits GDF-8 binding to GDF-8 receptor.  
     
     
         14 . A substantially purified GDF-11-binding agent, wherein the binding agent inhibits GDF-11 binding to GDF-11 receptor.  
     
     
         15 . The agent as in claims  13  or  14 , wherein the agent is selected from a biologic agent and a chemical compound.  
     
     
         16 . The agent as in claims  13  or  14 , wherein the agent is a anti-GDF antibody or epitope binding fragment thereof.  
     
     
         17 . The agent of  claim 16 , wherein the antibody is a monoclonal antibody or a polyclonal antibody.  
     
     
         18 . A method for inhibiting GDF binding to a GDF receptor comprising contacting GDF-receptor with an anti-GDF-antibody.  
     
     
         19 . The method of  claim 18 , wherein the contacting is by in vivo administration to a subject.  
     
     
         20 . The method of  claim 19 , wherein the anti-GDF-antibody is administered by intravenous, intramuscular or subcutaneous injections.  
     
     
         21 . The method of  claim 20 , wherein the anti-GDF-antibody is administered within a dose range of 0.1 ug/kg to 100 mg/kg.  
     
     
         22 . The method of  claim 20 , wherein the antibody is formulated in a pharmaceutically acceptable carrier.  
     
     
         23 . A method for identifying a GDF receptor polypeptide comprising: 
 a) incubating components comprising GDF polypeptide and a cell expressing a receptor or a soluble receptor under conditions sufficient to allow the GDF to bind to the receptor;    b) measuring the binding of the GDF polypeptide to the receptor; and    c) isolating the receptor.    
     
     
         24 . The method of  claim 23 , wherein the GDF is GDF-8 or GDF-11.  
     
     
         25 . A method for identifying a compound which binds to GDF receptor polypeptide comprising: 
 a) incubating components comprising the compound and GDF polypeptide under conditions sufficient to allow the components to interact; and    b) measuring the binding or effect of binding of the compound to GDF receptor polypeptide.    
     
     
         26 . The method of  claim 25 , wherein the compound is a peptide.  
     
     
         27 . The method of  claim 25 , wherein the compound is a peptidomimetic.  
     
     
         28 . The method of  claim 25 , wherein the GDF receptor is expressed in a cell.  
     
     
         29 . The method of  claim 28 , wherein the cell is the cell of  claim 1 .  
     
     
         30 . The method of  claim 25 , wherein measuring the ability of the compound to bind to GDF receptor is by detection of a reporter means.  
     
     
         31 . The method of  claim 30 , wherein the reporter means is selected from the group consisting of a radioisotope, a fluorescent compound, a bioluminescent compound, a chemiluminescent compound, a metal chelator, or an enzyme.  
     
     
         32 . A transgenic non-human animal having a phenotype characterized by expression of GDF-receptor polypeptide, the phenotype being conferred by a transgene contained in the somatic and germ cells of the animal, the transgene comprising a nucleic acid sequence which encodes GDF-receptor polypeptide.  
     
     
         33 . The transgenic non-human animal of  claim 32 , wherein the animal is selected from the group of species consisting of avian, bovine, ovine, piscine, murine, and porcine.  
     
     
         34 . A method for producing a transgenic non-human animal having a phenotype characterized by expression of GDF-receptor polypeptide otherwise not naturally occurring in the animal, the method comprising: 
 (a) introducing at least one transgene into a zygote of an animal, the transgene(s) comprising a DNA construct encoding GDF-receptor,    (b) transplanting the zygote into a pseudopregnant animal,    (c) allowing the zygote to develop to term, and    (d) identifying at least one transgenic offspring containing the transgene.    
     
     
         35 . The method of  claim 34 , wherein the introducing of the transgene into the embryo is by introducing an embryonic stem cell containing the transgene into the embryo.  
     
     
         36 . The method of  claim 34 , wherein the introducing of the transgene into the embryo is by infecting the embryo with a retrovirus containing the transgene.  
     
     
         37 . A transgenic non-human animal having a transgene disrupting or interfering with expression of GDF-receptor chromosomally integrated into the germ cells of the animal.  
     
     
         38 . The transgenic non-human animal of  claim 37 , wherein the transgene comprises GDF-receptor antisense polynucleotide.  
     
     
         39 . A method for inhibiting the expression of GDF-receptor in a cell comprising contacting GDF-receptor with an inhibiting effective amount of an antisense oligonucleotide that binds to a segment of an mRNA transcribed from a GDF-receptor gene, whereby the binding of the antisense to the mRNA segment inhibits GDF-receptor expression.  
     
     
         40 . Substantially pure GDF receptor polypeptide.  
     
     
         41 . The GDF receptor of  claim 40 , wherein GDF is GDF-8 or GDF-11.