Abstract: The invention provides a method of improving the efficiency of establishment of induced pluripotent stem cells by increasing, in a nuclear reprogramming step of somatic cell, the level of activated form of one or more proteins selected from the group consisting of Ras family members, PI3 kinase, RalGEF, Raf, AKT family members, Rheb, TCL1 and S6K. The invention also provides a method of producing induced pluripotent stem cells by contacting a somatic cell with a nuclear reprogramming substance and one or more of such proteins and nucleic acids that encode such proteins. The invention further provides an induced pluripotent stem cell that has an exogenous nucleic acid encoding such a protein, as well as agents for use in the aforesaid methods.

Abstract: A method for efficiently preparing blood cells, such as mature megakaryocytes and platelets, from iPS cells is achieved in an in vitro culture system. A sac-like structure encloses hematopoietic progenitor cells, which is obtained by inoculating iPS cells onto feeder cells and then culturing the iPS cells under conditions suitable for inducing the differentiation of hematopoietic progenitor cells. Moreover, a method for producing various types of blood cells, comprises culturing hematopoietic progenitor cells enclosed in the sac-like structure under conditions suitable for inducing the differentiation of blood cells. Furthermore, a method for producing various types of blood cells, particularly megakaryocytes and platelets, is achieved without involving the sac-like structure.

Abstract: The present invention provides a method of improving the efficiency of establishment of induced pluripotent stem (iPS) cells, comprising inhibiting the p53 function in the step of somatic cell nuclear reprogramming. The inhibition of p53 function is achieved by bringing a substance selected from the group consisting of (1) chemical inhibitors of p53, (2) dominant negative mutants of p53 and nucleic acids that encode the same, (3) siRNAs and shRNAs against p53 and DNAs that encode the same, and (4) p53 pathway inhibitors, into contact with a somatic cell, and the like. The present invention also provides an agent for improving the efficiency of establishment of iPS cells, the agent comprising an inhibitor of p53 function, particularly (1) chemical inhibitors of p53, (2) dominant negative mutants of p53 and nucleic acids that encode the same, (3) siRNAs and shRNAs against p53 and DNAs that encode the same, and (4) p53 pathway inhibitors.

Abstract: The present invention provides a method of improving the efficiency of establishment of induced pluripotent stem (iPS) cells by inhibiting p38 function in the step of somatic cell nuclear reprogramming. The p38 function can be inhibited by bringing an inhibitor selected from the group consisting of (1) a chemical inhibitor of p38 (2) a dominant negative mutant of p38 or a nucleic acid that encodes the same, (3) a nucleic acid selected from the group consisting of siRNAs and shRNAs targeted to p38 and DNAs that encode the same and (4) an inhibitor of p38 pathway into contact with a somatic cell and the like.

Abstract: Provided is a method of improving the efficiency of iPS cell establishment, comprising bringing one or more factors selected from the group consisting of proteins belonging to cyclin D family and nucleic acids that encode the same into contact with a somatic cell, in the step of nuclear reprogramming of the somatic cell. Also provided are a method of producing an iPS cell comprising the step of bringing the factor(s) and nuclear reprogramming substance(s) into contact with a somatic cell, an iPS cell comprising a nucleic acid that encodes a protein belonging to cyclin D family that can be obtained by the method of producing an iPS cell, and a method of somatic cell production by forcing the iPS cell to differentiate.

Abstract: A method of preparing induced pluripotent stem cells, comprising a nuclear reprogramming step with a nuclear reprogramming factor in the presence of miRNA, wherein said miRNA has a property of providing a higher nuclear reprogramming efficiency in the presence of said miRNA than in the absence thereof.

Abstract: The present invention provides a method for selecting human induced pluripotent stem (iPS) cells which can be safely used for transplantation. That is, the present invention provides a method for selecting human iPS cells having reduced differentiation resistance, comprising the steps of: (1) inducing differentiation of human iPS cells; (2) detecting remaining undifferentiated cells after the step (1); and (3) selecting human iPS cells whose rate of remaining undifferentiated cells detected in step (2) is equivalent to or not more than that of control cells.

Abstract: The present invention provides a method of selecting a highly safe induced pluripotent stem cell, which includes comprehensively detecting the sequence of an expression vector used for induction of the induced pluripotent stem cell, in the nucleic acid in the cell, and a kit used for the method.

Abstract: A method of producing an induced pluripotent stem cell includes introducing into a somatic cell one or more non-viral expression vectors. The vectors include one or more of an Oct family gene, a Klf family gene, a Sox family gene, a Myc family gene, a Lin family gene, and Nanog gene. The somatic cell is then cultured in a medium that supports pluripotent stem cells. At least a portion of the one or more introduced non-viral expression vectors is not substantially integrated in the chromosome.

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.

Abstract: Provided are a method of improving the efficiency of establishment of iPS cells, comprising the step of contacting one or more substances selected from the group consisting of members of the GLIS family (e.g., GLIS1) and nucleic acids that encode the same and one or more substances selected from the group consisting of members of the Klf family and nucleic acids that encode the same, with a somatic cell, an iPS cell comprising an exogenous nucleic acid that encodes a member of the GLIS family or a member of the Klf family, that can be obtained by the method, and a method of producing a somatic cell by inducing the differentiation of the iPS cell.

Abstract: The present invention relates to miRNA or genes expressed in induced pluripotent stem cells, and a method for screening for induced pluripotent stem cells having functions equivalent to those of embryonic stem cells by confirming methylation of specific gene regions of induced pluripotent stem cells.

Abstract: The present invention provides a method for improving iPS cell generation efficiency, which comprises a step of introducing a Myc variant having the following features: (1) having an activity to improve iPS cell generation efficiency which is comparative to, or greater than that of c-Myc; and (2) having a transformation activity which is lower than that of c-Myc; or a nucleic acid encoding the variant, in a nuclear reprogramming step. Also, the present invention provides a method for preparing iPS cells, which comprises a step of introducing the above Myc variant or a nucleic acid encoding the variant and a combination of nuclear reprogramming factors into somatic cells. Moreover, the present invention provides iPS cells comprising the nucleic acid encoding the Myc variant which can be obtained by the above method, and a method for preparing somatic cells which comprises inducing differentiation of the iPS cells.

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.

Abstract: Provided are a method of improving iPS cell establishment efficiency, comprising the step of transferring Lin28B or a nucleic acid that encodes Lin28B to a somatic cell, particularly to a somatic cell on which Lin28 is ineffective or less effective than Lin28B in improving iPS cell establishment efficiency, and a method of producing an iPS cell, comprising the step of transferring Lin28B or a nucleic acid that encodes Lin28B and a nuclear reprogramming substance to a somatic cell. Also provided are an iPS cell comprising a nucleic acid that encodes Lin28B, that can be obtained by the method of producing an iPS cell, and a method of somatic cell production by forcing the iPS cell to differentiate into a somatic cell.

Abstract: Provided is a method of producing an iPS cell, comprising bringing (a) Oct3/4 or a nucleic acid that encodes the same, (b) Klf4 or a nucleic acid that encodes the same, and (c) Sox2 or a nucleic acid that encodes the same, as well as (d1) L-Myc or a nucleic acid that encodes the same and/or (d2) a functional inhibitor of p53, into contact with a somatic cell. It is preferable that (a) a nucleic acid that encodes Oct3/4, (b) a nucleic acid that encodes Klf4, (c) a nucleic acid that encodes Sox2, (d1) a nucleic acid that encodes L-Myc and (e) a nucleic acid that encodes Lin28 or Lin28b be inserted into an episomal vector having loxP sequences placed in the same orientation on the 5? and 3? sides of a vector constituent essential for the replication of the vector, that (d2) a nucleic acid that encodes an shRNA against p53 be inserted into a vector ensuring transient expression (plasmid vector and the like), and that all these nucleic acids be transferred to a somatic cell.

Abstract: The invention provides an antibody that specifically binds to (a) a protein having an amino acid sequence depicted in SEQ ID NO:16 or 32 or (b) a protein which has an amino acid sequence of (a), wherein one to several amino acids are deleted, substituted, or added, and which is specifically expressed in an ES cell.

Abstract: Provided is a method of selecting highly safe pluripotent stem cells that do not exhibit differentiation resistance, comprising the steps of (1) inducing a pluripotent stem cell to differentiate, (2) culturing the cell under conditions for maintaining undifferentiated state, (3) detecting the generation of an undifferentiated cell by the cultivation, and comparing the finding with a control, and (4) selecting a pluripotent stem cell whose detected value is not more than a control generation value.

Abstract: The present invention relates to a method for selecting induced pluripotent stem (iPS) cells.

Abstract: The present invention relates to: a method for inducing differentiation into an epithelial progenitor cell/stem cell population or a corneal epithelial cell population by culturing, under particular conditions, induced pluripotent stem cells induced from mammalian somatic cells or undifferentiated stem cells; an epithelial progenitor cell/stem cell population or a corneal epithelial cell population obtained by the method; and a cell preparation for the treatment of epithelial disease and a cell sheet, which are prepared using these cell populations.