Methods and materials relating to novel stem cell growth factor-like polypeptides and polynucleotides

Abstract

The invention provides novel polynucleotides and polypeptides encoded by such polynucleotides and mutants or variants thereof that correspond to a novel human stem cell growth factor-like protein. These polynucleotides comprise nucleic acid sequences isolated from cDNA libraries from human testis cells (Hyseq clone identification numbers 2880984 and 2881695), from human fetal skin (Hyseq clone identification number 15375176), adult spleen (Hyseq clone identification number 14856094), and human endothelial cells (Hyseq clone identification numbers 13804756, 13687487, 13804756). Other aspects of the invention include vectors containing processes for producing novel human stem cell growth factor-like polypeptides, and antibodies specific for such polypeptides.

1 . A culture medium comprising an amount of a polypeptide having stem cell growth factor activity effective to maintain survival of or promote proliferation of a stem cell or germ cell, wherein said polypeptide comprises the amino acid sequence of SEQ ID NO:13, 16, 32 or 34, or the mature protein portion thereof, or a polypeptide with at least 98% sequence identity thereto. 
     
     
         2 . An antibody that binds to a polypeptide having stem cell growth factor activity, wherein said polypeptide comprises the amino acid sequence of SEQ ID NO: 13, 16, 32 or 34, or the mature protein portion thereof, or a polypeptide with at least 98% sequence identity thereto. 
     
     
         3 . The antibody of  claim 2  that specifically binds to a polypeptide comprising the amino acid sequence of SEQ ID NO: 13, 16, 32 or 34. 
     
     
         4 . The antibody of  claim 2  that does not bind to a polypeptide comprising the amino acid sequence of SEQ ID NO: 48. 
     
     
         5 . The antibody of  claim 2  that is a polyclonal antibody, monoclonal antibody, antibody fragment, chimeric antibody, or humanized antibody. 
     
     
         6 . A kit comprising the antibody of  claim 2 . 
     
     
         7 . A method for detecting a polynucleotide encoding a polypeptide with stem cell growth factor activity in a sample, wherein said polynucleotide comprises the nucleotide sequence of SEQ ID NO: 11, 12, 31 or 33, or a polynucleotide with at least 98% sequence identity thereto, said method comprising:
 a) contacting the sample with a compound that binds to and forms a complex with the polynucleotide for a period sufficient to form the complex; and   b) detecting the complex, so that if a complex is detected, the polynucleotide is detected.   
     
     
         8 . A method for detecting a polynucleotide encoding a polypeptide with stem cell growth factor activity in a sample, wherein said polynucleotide comprises the nucleotide sequence of SEQ ID NO: 11, 12, 31 or 33, or a polynucleotide with at least 98% sequence identity thereto, said method comprising:
 a) contacting the sample under stringent hybridization conditions with nucleic acid primers that anneal to the polynucleotide under such conditions;   b) amplifying a product comprising at least a portion of the polynucleotide; and   c) detecting said product and thereby the polynucleotide in the sample.   
     
     
         9 . The method of  claim 8 , wherein the polynucleotide is an RNA molecule that encodes a polypeptide comprising the amino acid sequence of SEQ ID NO: 13, 16, 32 or 34, or the mature protein portion thereof, or a polypeptide with at least 98% sequence identity thereto, and further wherein the method comprises reverse transcribing an annealed RNA molecule into a cDNA polynucleotide. 
     
     
         10 . A method for detecting a polypeptide with stem cell growth factor activity in a sample, wherein said polypeptide comprises the amino acid sequence of SEQ ID NO: 13, 16, 32 or 34, or the mature protein portion thereof, or a polypeptide with at least 98% sequence identity thereto, said method comprising:
 a) contacting the sample with a compound that binds to and forms a complex with the polypeptide under conditions and for a period sufficient to form the complex; and   b) detecting formation of the complex, so that if a complex formation is detected, the polypeptide is detected.   
     
     
         11 . A method for identifying a compound that binds to a polypeptide with stem cell growth factor activity in a sample, wherein said polypeptide comprises the amino acid sequence of SEQ ID NO:13, 16, 32 or 34, or the mature protein portion thereof, or a polypeptide with at least 98% sequence identity thereto, said method comprising:
 a) contacting the compound with the polypeptide under conditions and for a time sufficient to form a polypeptide/compound complex; and   b) detecting the complex, so that if the polypeptide/compound complex is detected, a compound that binds to the polypeptide is identified.   
     
     
         12 . A method for identifying a compound that binds to a polypeptide with stem cell growth factor activity in a sample, wherein said polypeptide comprises the amino acid sequence of SEQ ID NO: 13, 16, 32 or 34, or the mature protein portion thereof, or a polypeptide with at least 98% sequence identity thereto, said method comprising:
 a) contacting the compound with the polypeptide, in a cell, for a time sufficient to form a polypeptide/compound complex, wherein the complex drives expression of a reporter gene sequence in the cell; and   b) detecting the complex by detecting reporter gene sequence expression, so that if the polypeptide/compound complex is detected, a compound that binds to the polypeptide is identified.   
     
     
         13 . A nucleic acid array comprising a polynucleotide encoding a polypeptide with stem cell growth factor activity, wherein said polynucleotide comprises the nucleotide sequence of SEQ ID NO: 11, 12, 31 or 33, or a polynucleotide with at least 98% sequence identity thereto, or a unique segment of the polynucleotide, wherein said polynucleotide is attached to a surface. 
     
     
         14 . The array of  claim 13 , wherein the array detects full-matches to the polynucleotide or a unique segment of the polynucleotide. 
     
     
         15 . The array of  claim 13 , wherein the array detects mismatches to the polynucleotide or a unique segment of the polynucleotide. 
     
     
         16 . A method of treating a subject in need of enhanced activity or expression of a stem cell growth factor-like polypeptide, wherein the polypeptide comprises the amino acid sequence of SEQ ID NO: 13, 16, 32 or 34, or the mature protein portion thereof, or a polypeptide with at least 98% sequence identity thereto, said method comprising administering to the subject:
 (a) a composition comprising a therapeutic amount of an agonist of said polypeptide;   (b) a composition comprising a therapeutic amount of the polypeptide; or   (c) a composition comprising a therapeutic amount of a polynucleotide encoding the polypeptide in form and under conditions such that the polypeptide is produced; said composition comprising a pharmaceutically acceptable carrier or diluent.   
     
     
         17 . A method of treating a subject having need of decreased activity or expression of a stem cell growth factor-like polypeptide, wherein the polypeptide comprises the amino acid sequence of SEQ ID NO: 13, 16, 32 or 34, or the mature protein portion thereof, or a polypeptide with at least 98% sequence identity thereto, said method comprising administering to the subject:
 (a) a composition comprising a therapeutic amount of an antagonist of said polypeptide;   (b) a composition comprising a therapeutic amount of the polynucleotide that inhibits the expression of the nucleotide sequence encoding said polypeptide; or   (c) a composition comprising a therapeutic amount of a polypeptide that competes with the stem cell growth factor-like polypeptide for its ligand; said composition comprising a pharmaceutically acceptable carrier or diluent.   
     
     
         18 . A method of supporting proliferation or survival of a stem cell or germ cell comprising contacting said cell with an amount of a polypeptide effective to maintain survival of or promote proliferation of said cell, wherein the polypeptide comprises the amino acid sequence of SEQ ID NO:13, 16, 32 or 34, or the mature protein portion thereof, or a polypeptide with at least 98% sequence identity thereto. 
     
     
         19 . The method of  claim 18 , wherein said cell is a primordial germ cell, germ line stem cell, embryonic stem cell, hematopoietic stem cell, hematopoietic progenitor cell, pluripotent cell, or totipotent cell. 
     
     
         20 . A stromal cell genetically engineered to express a polypeptide in an amount effective to support proliferation or survival of a stem cell or germ cell, wherein the polypeptide comprises the amino acid sequence of SEQ ID NO: 13, 16, 32 or 34, or the mature protein portion thereof, or a polypeptide with at least 98% sequence identity thereto. 
     
     
         21 . The stromal cell of  claim 20  wherein said cell is a primordial germ cell, germ line stem cell, embryonic stem cell, hematopoietic stem cell, hematopoietic progenitor cell, pluripotent cell, or totipotent cell. 
     
     
         22 . An implant comprising a cell genetically engineered to express a polypeptide in an amount effective to support proliferation or survival of a stem cell or germ cell, wherein the polypeptide comprises the amino acid sequence of SEQ ID NO: 13, 16, 32 or 34, or the mature protein portion thereof, or a polypeptide with at least 98% sequence identity thereto. 
     
     
         23 . The implant of  claim 22  wherein said cell is a primordial germ cell, germ line stem cell, embryonic stem cell, hematopoietic stem cell hematopoietic progenitor cell pluripotent cell, or totipotent cell.