Induced pluripotent stem cells produced with oct3/4, klf and sox

Abstract

The present invention relates to a nuclear reprogramming factor having an action of reprogramming a differentiated somatic cell to derive an induced pluripotent stem (iPS) cell. The present invention also relates to the aforementioned iPS cells, methods of generating and maintaining iPS cells, and methods of using iPS cells, including screening and testing methods as well as methods of stem cell therapy. The present invention also relates to somatic cells derived by inducing differentiation of the aforementioned iPS cells.

1 . A method for preparing a mammalian induced pluripotent stem cell which comprises:
 a) forcing expression of a group of gene products that comprises at least one of an Oct3/4 gene product, a Klf family gene product, and a Sox family gene product in a mammalian somatic cell, so that the introduced mammalian somatic cell expresses all three of a Oct3/4 gene product, a Klf family gene product and a Sox family gene product,   b) culturing the mammalian somatic cell obtained after step (a) under conditions that maintain pluripotency and self-renewal.   
     
     
         2 . The method of  claim 1 , wherein forced expression comprises introducing one or more expression vectors containing genes encoding said gene products. 
     
     
         3 . The method of  claim 1 , wherein the mammalian somatic cell endogenously expresses at least one of Oct3/4 gene product, a Klf family gene product and a Sox family gene product. 
     
     
         4 . The method of  claim 1 , wherein the Klf family gene is Klf2 gene or Klf4 gene, and the Sox family gene is selected from group consisting of Sox1 gene, Sox2 gene, Sox3 gene, Sox15 gene and Sox17 gene. 
     
     
         5 . The method of  claim 4 , wherein the Klf family gene is Klf4 gene, and the Sox family gene is Sox2 gene. 
     
     
         6 . The method of  claim 1 , wherein the mammalian somatic cell is forced to express a Myc family gene product, wherein the Myc family gene is selected from the group consisting of L-Myc gene, N-Myc gene, and c-Myc gene. 
     
     
         7 . The method of  claim 1 , wherein the mammalian somatic cell is a human somatic cell. 
     
     
         8 . The method of  claim 1 , wherein the conditions that maintain pluripotency and self-renewal comprise culturing in the presence of bFGF and/or SCF. 
     
     
         9 . A method of preparing a mammalian somatic cell derived from a mammalian induced pluripotent stem cell, comprising
 preparing the mammalian induced pluripotentent stem cell according to  claim 1 , and   inducing differentiation of the mammalian induced pluripotent stem cell to prepare the mammalian somatic cell derived from the mammalian induced pluripotent stem cell.   
     
     
         10 . A method for preparing a mammalian induced pluripotent stem cell which comprises:
 a) contacting a mammalian somatic cell with a group of gene products that comprises at least one of an Oct3/4 gene product, a Klf family gene product, and a Sox family gene product, and introducing into the mammalian somatic cell a group of genes that comprises zero to all three of an Oct3/4 gene, a Klf family gene, and a Sox family gene, wherein each said gene is encoded by one or more expression vectors, so that the resulting mammalian somatic cell is contacted with and/or expresses all three of a Oct3/4 gene product, a Klf family gene product and a Sox family gene product in total   b) culturing the mammalian somatic cell obtained after step (a) under conditions that maintain pluripotency and self-renewal.   
     
     
         11 . The method of  claim 10 , wherein the mammalian somatic cell endogenously expresses at least one of Oct3/4 gene product, a Klf family gene product and a Sox family gene product. 
     
     
         12 . The method of  claim 10 , wherein the Klf family gene product is Klf2 gene product or Klf4 gene product, and the Sox family gene product is selected from group consisting of Sox1 gene product, Sox2 gene product, Sox3 gene product, Sox15 gene product and Sox17 gene product. 
     
     
         13 . The method of  claim 12 , wherein the Klf family gene product is Klf4 gene product, and the Sox family gene product is Sox2 gene product. 
     
     
         14 . The method of  claim 10 , wherein the mammalian somatic cell obtained step (a) further expresses or is contacted with a Myc family gene product. 
     
     
         15 . The method of  claim 14 , wherein the group of gene products further comprises the Myc family gene product and/or the group of genes further comprises the Myc family gene. 
     
     
         16 . The method of  claim 10 , wherein the mammalian somatic cell is a human somatic cell. 
     
     
         17 . The method of  claim 10 , wherein the conditions that maintain pluripotency and self-renewal comprise culturing in the presence of bFGF and/or SCF. 
     
     
         18 . A method of preparing a mammalian somatic cell derived from a mammalian induced pluripotent stem cell, comprising
 preparing the mammalian induced pluripotentent stem cell according to  claim 10 , and   inducing differentiation of the mammalian induced pluripotent stem cell to prepare the mammalian somatic cell derived from the mammalian induced pluripotent stem cell.