Multipotent/Pluripotent Cells and Methods

1 - 132 . (canceled)

133 . A pluripotent stem cell induced by reprogramming a somatic cell, wherein the reprogramming is performed in the absence of eggs, embryos, or embryonic stem (ES) cells.

134 . The pluripotent stem cell of claim 133 , wherein the somatic cell is a human cell.

135 . The pluripotent stem cell of claim 133 , wherein the somatic cell is a mouse cell.

136 . The pluripotent stem cell of claim 133 , wherein the reprogramming comprises contacting the somatic cell with a nuclear reprogramming factor.

137 . The pluripotent stem cell of claim 136 , wherein the nuclear reprogramming factor comprises at least one gene product.

138 . The pluripotent stem cell of claim 137 , wherein the nuclear reprogramming factor comprises a protein.

139 . The pluripotent stem cell of claim 136 , wherein the nuclear reprogramming factor is encoded by a gene contained in a recombinant vector introduced into the cell.

140 . The pluripotent stem cell of claim 136 , wherein the nuclear reprogramming factor comprises a gene product of an Oct family gene.

141 . The pluripotent stem cell of claim 136 , wherein the nuclear reprogramming factor comprises a gene product of a Klf family gene.

142 . The pluripotent stem cell of claim 136 , wherein the nuclear reprogramming factor comprises a gene product of a Myc family gene.

143 . The pluripotent stem cell of claim 136 , wherein the nuclear reprogramming factor comprises a gene product of a Sox family gene.

144 . The pluripotent stem cell of claim 136 , wherein the nuclear reprogramming factor comprises one or more gene products of each of: an Oct family gene, a Klf family gene, and a Myc family gene.

145 . The pluripotent stem cell of claim 136 , wherein the nuclear reprogramming factor comprises one or more gene products of each of: an Oct family gene, a Klf family gene, and a Sox family gene.

146 . The pluripotent stem cell of claim 145 , wherein the nuclear reprogramming factor comprises one or more gene products of each of: Oct3/4, Klf4, and Sox2.

147 . The pluripotent stem cell of claim 136 , wherein the nuclear reprogramming factor comprises one or more gene products of each of: an Oct family gene, a Klf family gene, a Myc family gene, and a Sox family gene.

148 . The pluripotent stem cell of claim 147 , wherein the nuclear reprogramming factor comprises one or more gene products of each of: Oct3/4, Klf4, c Myc, and Sox2.

149 . The pluripotent stem cell of claim 136 , wherein the nuclear reprogramming factor comprises one or more gene products of each of: Klf4, c Myc, Oct3/4, Sox2, Nanog, and Lin28.

150 . The pluripotent stem cell of claim 136 , wherein the nuclear reprogramming factor comprises one or more gene products of each of: an Oct family gene, a Klf family gene, together with a cytokine.

151 . The pluripotent stem cell of claim 150 , wherein the cytokine comprises fibroblast growth factor (bFGF).

152 . The pluripotent stem cell of claim 151 , wherein the cytokine comprises basic fibroblast growth factor (bFGF) and another growth factor.

153 . The pluripotent stem cell of claim 150 , wherein the nuclear reprogramming factor further comprises a Myc family gene.

154 . The pluripotent stem cell of claim 150 , wherein the nuclear reprogramming factor further comprises a gene product of a Sox family gene.

155 . The pluripotent stem cell of claim 153 , wherein the cytokine comprises basic fibroblast growth factor (bFGF).

156 . The pluripotent stem cell of claim 155 , wherein the cytokine comprises basic fibroblast growth factor (bFGF) and another growth factor.

157 . The pluripotent stem cell of claim 154 , wherein the cytokine comprises at least one of basic fibroblast growth factor (bFGF) and another growth factor.

158 . The pluripotent stem cell of claim 147 , wherein the nuclear reprogramming factor further comprises a gene product of the TERT gene.

159 . The pluripotent stem cell of claim 147 , wherein the nuclear reprogramming factor further comprises one or more gene products of one or more kinds of the following genes: Nanog, ECAT1, and Tc11.

160 . The pluripotent stem cell of claim 147 , wherein the nuclear reprogramming factor further comprises one or more gene products of one or more kinds of the following genes: ECAT1 or Dnmt3B.

161 . A method for preparing an induced pluripotent stem cell by nuclear reprogramming of a somatic cell, which comprises contacting a nuclear reprogramming factor with the somatic cell to obtain an induced pluripotent stem cell.

162 . The method of claim 161 , wherein the nuclear reprogramming factor comprises one or more gene products of each of: an Oct family gene, a Klf family gene, and a Sox family gene.

163 . The method of claim 162 wherein the nuclear reprogramming factor further comprises a cytokine.

164 . The method of claim 163 , wherein the cytokine comprises basic fibroblast growth factor (bFGF).

165 . The method of claim 164 , wherein the cytokine comprises basic fibroblast growth factor (bFGF) and another growth factor.

166 . The method of claim 161 , wherein the nuclear reprogramming factor comprises one or more gene products of each of: an Oct family gene, a Klf family gene, a Sox family gene, and a Myc family gene.

167 . The method of claim 166 , wherein the nuclear reprogramming factor comprises one or more gene products of each of: Oct3/4, Klf4, c Myc, and Sox2.

168 . The method of claim 161 , wherein the nuclear reprogramming factor comprises one or more gene products of each of: Klf4, c Myc, Oct3/4, Sox2, Nanog, and Lin28.

169 . The method of claim 161 , wherein the somatic cell is a human cell.

170 . The method of claim 161 , wherein the somatic cell is a mouse cell.

171 . The method of claim 161 , wherein the contacting comprises contacting the nuclear reprogramming factor with the somatic cell in the absence of eggs, embryos, or embryonic stem (ES) cells.

172 . The method of claim 171 , wherein the nuclear reprogramming factor comprises one or more gene products of each of: an Oct family gene, a Klf family gene, and a Sox family gene.

173 . The method of claim 171 , wherein the nuclear reprogramming factor comprises one or more gene products of each of: an Oct family gene, a Klf family gene, and a Myc family gene.

174 . The method of claim 172 wherein the nuclear reprogramming factor further comprises a cytokine.

175 . The method of claim 173 , wherein the nuclear reprogramming factor further comprises a cytokine.

176 . The method of claim 172 , wherein the nuclear reprogramming factor comprises one or more gene products of each of: an Oct3/4 gene, a Klf4 gene, and a Sox2 gene.

177 . The method of claim 171 , wherein the nuclear reprogramming factor comprises one or more gene products of each of: an Oct family gene, a Klf family gene, a Sox family gene, and a Myc family gene.

178 . The method of claim 177 , wherein the nuclear reprogramming factor comprises one or more gene products of each of: Oct3/4, Klf4, c Myc, and Sox2.

179 . The method of claim 171 , wherein the nuclear reprogramming factor comprises one or more gene products of each of: Klf4, c Myc, Oct3/4, Sox2, Nanog, and Lin28.

180 . The method of claim 177 , wherein the nuclear reprogramming factor further comprises a gene product of the TERT gene.

181 . The method of claim 177 , wherein the nuclear reprogramming factor further comprises one or more gene products of one or more kinds of the following genes: Nanog or Tc11.

182 . The method of claim 177 , wherein the nuclear reprogramming factor further comprises one or more gene products of one or more kinds of the following genes: ECAT1 or Dnmt3B.

183 . The method of claim 171 , wherein the nuclear reprogramming factor comprises one or more gene products of each of: an Oct family gene, a Klf family gene, together with a cytokine.

184 . The method of claim 183 , wherein the cytokine comprises basic fibroblast growth factor (bFGF).

185 . The method of claim 184 , wherein the cytokine comprises basic fibroblast growth factor (bFGF) and another growth factor.

186 . The method of claim 183 , wherein the nuclear reprogramming factor further comprises a Myc family gene.

187 . The method of claim 186 , wherein the cytokine comprises basic fibroblast growth factor (bFGF).

188 . The method of claim 187 , wherein the cytokine comprises basic fibroblast growth factor (bFGF) and another growth factor.

189 . The method of claim 183 , wherein the nuclear reprogramming factor further comprises a Sox family gene.

190 . The method of claim 189 , wherein the cytokine comprises basic fibroblast growth factor (bFGF).

191 . The method of claim 190 , wherein the cytokine comprises basic fibroblast growth factor (bFGF) and another growth factor.

192 . The method of claim 171 , wherein the somatic cell is a human cell.

193 . The method of claim 171 , wherein the somatic cell is a mouse cell.

194 . A method of inducing a somatic cell to become a pluripotent stem cell comprising contacting the somatic cell with a nuclear reprogramming factor under conditions to obtain a pluripotent stem cell free of rejection.

195 . An induced pluripotent stem cell obtained by the method of claim 161 .

196 . An induced pluripotent stem cell obtained by the method of claim 171 .

197 . A somatic cell derived by inducing differentiation of the pluripotent stem cell according to claim 195 .

198 . A somatic cell derived by inducing differentiation of the pluripotent stem cell according to claim 196 .

199 . A somatic cell derived by inducing differentiation of the pluripotent stem cell according to claim 133 .

200 . A method for stem cell therapy comprising: (1) isolating and collecting a somatic cell from a patient; (2) inducing said somatic cell from the patient into an iPS cell (3) inducing differentiation of said iPS cell, and (4) transplanting the differentiated cell from (3) into the patient.

201 . A pluripotent stem cell induced by reprogramming a somatic cell, wherein the reprogramming comprises contacting the somatic cell with a nuclear reprogramming factor.

202 . The pluripotent stem cell of claim 201 , wherein the somatic cell is a human cell.

203 . The pluripotent stem cell of claim 201 , wherein the somatic cell is a mouse cell.

204 . The pluripotent stem cell of claim 201 , wherein the nuclear reprogramming factor comprises one or more gene products of each of: an Oct family gene, a Klf family gene, and a Myc family gene.

205 . The pluripotent stem cell of claim 201 , wherein the nuclear reprogramming factor comprises one or more gene products of each of: an Oct family gene, a Klf family gene, and a Sox family gene.

206 . The pluripotent stem cell of claim 205 , wherein the nuclear reprogramming factor comprises one or more gene products of each of: Oct3/4, Klf4, and Sox2.

207 . The pluripotent stem cell of claim 201 , wherein the nuclear reprogramming factor comprises one or more gene products of each of: an Oct family gene, a Klf family gene, a Myc family gene, and a Sox family gene.

208 . The pluripotent stem cell of claim 207 , wherein the nuclear reprogramming factor comprises one or more gene products of each of: Oct3/4, Klf4, c Myc, and Sox2.

209 . The pluripotent stem cell of claim 201 , wherein the nuclear reprogramming factor comprises one or more gene products of each of: an Oct family gene, a Klf family gene, together with a cytokine.

210 . The pluripotent stem cell of claim 209 , wherein the nuclear reprogramming factor further comprises a Myc family gene.

211 . The pluripotent stem cell of claim 209 , wherein the nuclear reprogramming factor further comprises a gene product of a Sox family gene.

212 . A somatic cell derived by inducing differentiation of the pluripotent stem cell according to claim 201 .

213 . A nuclear reprogramming factor for a somatic cell, which comprises a gene product of each of the following three kinds of genes: an Oct family gene, a Klf family gene, and a Myc family gene.

214 . The factor according to claim 213 , which comprises a gene product of each of the following three kinds of genes: Oct3/4, Klf4, and c-Myc.

215 . The factor according to claim 213 , which further comprises a gene product of the following gene: a Sox family gene.

216 . The factor according to claim 215 , which comprises a gene product of Sox2.

217 . The factor according to claim 213 , which comprises a cytokine together with a gene product of the Myc family gene.

218 . The factor according to claim 217 , wherein the cytokine is basic fibroblast growth factor (bFGF).

219 . The factor according to claim 213 , which further comprises a gene product of the following gene: TERT gene.

220 . The factor according to claim 213 , which further comprises a gene product or gene products of one or more kinds of the following genes: Nanog, ECAT1, and Tc11.

221 . The factor according to claim 213 , which further comprises a gene product or gene products of one or more kinds of the following genes: ECAT1 or Dnmt3.

222 . A method for preparing an induced pluripotent stem cell by nuclear reprogramming of a somatic cell, which comprises contacting the nuclear reprogramming factor according to claim 213 with the somatic cell in the absence of eggs, embryos, or embryonic stem (ES) cells.

223 . The method according to claim 222 , wherein the somatic cell is a human cell.

224 . An induced pluripotent stem cell obtained by the method according to claim 222 .

225 . A somatic cell derived by inducing differentiation of the induced pluripotent stem cell according to claim 224 .

226 . A method for improving differentiation ability and/or growth ability of a cell, which comprises contacting the nuclear reprogramming factor according to claim 213 with the cell.

227 . The method according to claim 226 , wherein the cell is a human cell.

228 . A cell obtained by the method according to claim 226 .

229 . A somatic cell derived by inducing differentiation of the cell according to claim 228 .

230 . A nuclear reprogramming factor for a somatic cell, which comprises a gene product of each of the following three kinds of genes: an Oct family gene, a Klf family gene, and a cytokine.

231 . The factor according to claim 230 , wherein the cytokine is bFGF.

232 . The cell according to claim 224 , which is a human cell.

233 . The cell according to claim 224 , which is a mouse cell.

234 . The cell according to claim 225 , which is a human cell.

235 . The cell according to claim 225 , which is a mouse cell.

236 . The method according to claim 222 , wherein the nuclear reprogramming factor comprises a gene product of each of the following three kinds of genes: an Oct family gene, a Klf family gene, and a Myc family gene.

237 . The method according to claim 222 , wherein the nuclear reprogramming factor comprises a gene product of each of the following three kinds of genes: Oct3/4, Klf4, and c Myc.

238 . The method according to claim 236 , wherein the nuclear reprogramming factor further comprises a gene product of the following gene: a Sox family gene.

239 . The method according to claim 238 , wherein the nuclear reprogramming factor comprises a gene product of Sox2.

240 . The method according to claim 222 , wherein the contacting is in the absence of eggs, embryos, or embryonic stem (ES) cells.

241 . A pluripotent stem cell induced from a somatic cell, wherein said somatic cell is non embryonic.

242 . The pluripotent stem cell of claim 241 , wherein the somatic cell is a human cell.

243 . The pluripotent stem cell of claim 241 , wherein the somatic cell is a mouse cell.

244 . The pluripotent stem cell of claim 241 , wherein the somatic cell is not a mouse cell.

245 . The pluripotent stem cell of claim 241 , wherein the inducing comprises contacting the somatic cell with a factor.

246 . The pluripotent stem cell of claim 241 , wherein the inducing comprises contacting the somatic cell with an induction factor.

247 . The pluripotent stem cell of claim 245 , wherein the factor comprises a gene product.

248 . The pluripotent stem cell of claim 245 , wherein the factor comprises a polypeptide.

249 . The pluripotent stem cell of claim 245 , wherein the factor is encoded by a gene contained in a recombinant vector introduced into the cell.

250 . The pluripotent stem cell of claim 245 , wherein the factor comprises an Oct family polypeptide.

251 . The pluripotent stem cell of claim 245 , wherein the factor comprises a Klf family polypeptide.

252 . The pluripotent stem cell of claim 245 , wherein the induction factor comprises a Myc family polypeptide.

253 . The pluripotent stem cell of claim 245 , wherein the factor comprises a Sox family polypeptide

254 . The pluripotent stem cell of claim 245 , wherein the factor comprises one or more: an Oct family polypeptide, a Klf family polypeptide, and a Myc family polypeptide.

255 . The pluripotent stem cell of claim 245 , wherein the factor comprises one or more: an Oct family polypeptide, a Klf family polypeptide, and a Sox family polypeptide.

256 . The pluripotent stem cell of claim 255 , wherein the factor comprises one or more: Oct3/4, Klf4, and Sox2 polypeptides.

257 . The pluripotent stem cell of claim 245 , wherein the factor comprises one or more: an Oct family polypeptide, a Klf family polypeptide, a Myc family polypeptide, and a Sox family polypeptide.

258 . The pluripotent stem cell of claim 245 , wherein the factor comprises one or more: Oct3/4, Klf4, c Myc, and Sox2 polypeptides.

259 . The pluripotent stem cell of claim 245 , wherein the factor comprises one or more: Klf4, c Myc, Oct3/4, Sox2, Nanog, and Lin28 polypeptides.

260 . The pluripotent stem cell of claim 245 , wherein the factor comprises one or more: an Oct family polypeptide, a Klf family polypeptide, together with a growth factor.

261 . The pluripotent stem cell of claim 260 , wherein the growth factor comprises basic fibroblast growth factor (bFGF).

262 . The pluripotent stem cell of claim 261 , wherein the growth factor comprises basic fibroblast growth factor (bFGF) and another growth factor.

263 . The pluripotent stem cell of claim 260 , wherein the factor further comprises a Myc family gene or polypeptide.

264 . The pluripotent stem cell of claim 260 , wherein the factor further comprises a Sox family polypeptide.

265 . The pluripotent stem cell of claim 263 , wherein the growth factor comprises basic fibroblast growth factor (bFGF).

266 . The pluripotent stem cell of claim 265 , wherein the growth factor comprises basic fibroblast growth factor (bFGF) and another growth factor.

267 . The pluripotent stem cell of claim 264 , wherein the growth factor comprises basic fibroblast growth factor (bFGF).

268 . The pluripotent stem cell of claim 257 , wherein the factor further comprises a TERT polypeptide.

269 . The pluripotent stem cell of claim 257 , wherein the factor further comprises one or more: Nanog, ECAT1, and Tc11 polypeptides.

270 . The pluripotent stem cell of claim 257 , wherein the factor further comprises one or more: ECAT1 or Dnmt3B.

271 . A method for preparing an induced pluripotent stem cell by inducing pluripotency of a somatic cell, which comprises contacting a factor with the somatic cell to obtain an induced pluripotent stem cell.

272 . The method of claim 271 , wherein the factor is an induction factor.

273 . The method of claims 271 or 272 , wherein the factor comprises one or more: an Oct family polypeptide, a Klf family polypeptide, and a Sox family polypeptide.

274 . The method of claim 273 , wherein the inducing further comprises contacting the somatic cell with a growth factor.

275 . The method of claim 274 , wherein the growth factor comprises basic fibroblast growth factor (bFGF).

276 . The method of claim 271 , wherein the growth factor comprises basic fibroblast growth factor (bFGF) and another growth factor.

277 . The method of claim 271 , wherein the factor comprises one or more: an Oct family polypeptide, a Klf family polypeptide, a Sox family polypeptide, and a Myc family polypeptide.

278 . The method of claim 277 , wherein the factor comprises one or more: Oct3/4, Klf4, c Myc, and Sox2 polypeptides.

279 . The method of claim 271 , wherein the factor comprises one or more: Klf4, c Myc, Oct3/4, Sox2, Nanog, and Lin28 polypeptides.

280 . The method of claim 271 , wherein the somatic cell is a human cell.

281 . The method of claim 271 , wherein the somatic cell is a mouse cell.

282 . The method of claim 271 , wherein the somatic cell is not a mouse cell.

283 . The method of claim 271 , wherein said somatic cell is non embryonic.

284 . The method of claim 283 , wherein the factor comprises one or more: an Oct family polypeptide, a Klf family polypeptide, and a Sox family polypeptide.

285 . The method of claim 283 , wherein the factor comprises one or more: an Oct family polypeptide, a Klf family polypeptide, and a Myc family polypeptide.

286 . The method of claim 284 wherein the factor further comprises a growth factor.

287 . The method of claim 285 , wherein the factor further comprises a growth factor.

288 . The method of claim 284 , wherein the inducing comprises one or more: an Oct3/4 gene, a Klf4 gene, and a Sox2 polypeptide.

289 . The method of claim 283 , wherein the factor comprises one or more: an Oct family polypeptide, a Klf family polypeptide, a Sox family polypeptide, and a Myc family polypeptide.

290 . The method of claim 289 , wherein the factor comprises one or more: Oct3/4, Klf4, c Myc, and Sox2 polypeptides.

291 . The method of claim 283 , wherein the factor comprises one or more: Klf4, c Myc, Oct3/4, Sox2, Nanog, and Lin28 polypeptides.

292 . The method of claim 289 , wherein the factor further comprises a TERT polypeptide.

293 . The method of claim 289 , wherein the factor further comprises one or more: Nanog or Tc11 polypeptides.

294 . The method of claim 289 , wherein the factor further comprises one or more: ECAT1 or Dnmt3B polypeptides.

295 . The method of claim 283 , wherein the factor comprises one or more: an Oct family polypeptide, a Klf family polypeptide, together with a growth factor.

296 . The method of claim 295 , wherein the growth factor comprises basic fibroblast growth factor (bFGF).

297 . The method of claim 295 , wherein the growth factor comprises basic fibroblast growth factor (bFGF) and another growth factor.

298 . The method of claim 295 , wherein the factor further comprises a Myc family polypeptide.

299 . The method of claim 298 , wherein the growth factor comprises basic fibroblast growth factor (bFGF).

300 . The method of claim 299 , wherein the growth factor comprises basic fibroblast growth factor (bFGF) and another growth factor.

301 . The method of claim 295 , wherein the factor further comprises a Sox family polypeptide.

302 . The method of claim 301 , wherein the growth factor comprises basic fibroblast growth factor (bFGF).

303 . The method of claim 302 , wherein the growth factor comprises basic fibroblast growth factor (bFGF) and another growth factor.

304 . The method of claim 283 , wherein the somatic cell is a human cell.

305 . The method of claim 283 , wherein the somatic cell is a mouse cell.

306 . The method of claim 283 , wherein the somatic cell is not a mouse cell.

307 . A method of inducing a somatic cell to become a pluripotent stem cell comprising contacting the somatic cell with a factor under conditions to obtain a pluripotent stem cell capable of overcoming immune rejection.

308 . The method of claim 307 , wherein the factor is an induction factor.

309 . An induced pluripotent stem cell obtained by the method of claim 271 .

310 . An induced pluripotent stem cell obtained by the method of claim 283 .

311 . A somatic cell derived by inducing differentiation of the pluripotent stem cell according to claim 309 .

312 . A somatic cell derived by inducing differentiation of the pluripotent stem cell according to claim 310 .

313 . A somatic cell derived by inducing differentiation of the pluripotent stem cell according to claim 241 .

314 . A method for stem cell therapy comprising: (1) isolating and collecting a somatic cell from a subject; (2) inducing said somatic cell into an iPS cell (3) inducing differentiation of said iPS cell, and (4) transplanting the differentiated cell from (3) into the subject.

315 . A pluripotent stem cell induced from a somatic cell, wherein the inducing comprises contacting the somatic cell with a factor.

316 . The pluripotent stem cell of claim 315 , wherein the somatic cell is a human cell.

317 . The pluripotent stem cell of claim 315 , wherein the somatic cell is a mouse cell.

318 . The pluripotent stem cell of claim 315 , wherein the somatic cell is not a mouse cell.

319 . The pluripotent stem cell of claim 315 , wherein the factor is an induction factor.

320 . The pluripotent stem cell of claim 315 , wherein the factor comprises one or more: an Oct family polypeptide, a Klf family polypeptide, and a Myc family polypeptide.

321 . The pluripotent stem cell of claim 315 , wherein the factor comprises one or more: an Oct family polypeptide, a Klf family polypeptide, and a Sox family polypeptide.

322 . The pluripotent stem cell of claim 321 , wherein the factor comprises one or more: Oct3/4, Klf4, and Sox2 polypeptides.

323 . The pluripotent stem cell of claim 315 , wherein the factor comprises one or more: an Oct family polypeptide, a Klf family polypeptide, a Myc family polypeptide, and a Sox family polypeptide.

324 . The pluripotent stem cell of claim 323 , wherein the factor comprises one or more: Oct3/4, Klf4, c Myc, and Sox2 polypeptides.

325 . The pluripotent stem cell of claim 315 , wherein the factor comprises one or more: an Oct family polypeptide, a Klf family polypeptide, together with a growth factor.

326 . The pluripotent stem cell of claim 325 , wherein the factor further comprises a Myc family polypeptide.

327 . The pluripotent stem cell of claim 325 , wherein the factor further comprises a Sox family polypeptide.

328 . A somatic cell derived by inducing differentiation of the pluripotent stem cell according to claims 315 .

329 . A factor for a somatic cell, which comprises: an Oct family polypeptide, a Klf family polypeptide, and a Myc family polypeptide.

330 . The factor of claim 329 , wherein the factor is an induction factor.

331 . The factor according to claim 329 , which comprises a gene product of each of the following three kinds of genes: Oct3/4, Klf4, and c-Myc.

332 . The factor according to claim 329 , which further comprises a gene product of the following gene: a Sox family gene.

333 . The factor according to claim 332 , which comprises a gene product of Sox2.

334 . The factor according to claim 329 , which comprises a growth factor together with a gene product of the Myc family gene.

335 . The factor according to claim 334 , wherein the growth factor is basic fibroblast growth factor (bFGF).

336 . The factor according to claim 329 , which further comprises a TERT polypeptide.

337 . The factor according to claim 329 , which further comprises a one or more: Nanog, ECAT1, or Tc11 polypeptides.

338 . The factor according to claim 329 , which further comprises one or more: ECAT1 or Dnmt3 polypeptides.

339 . A method for preparing an induced pluripotent stem cell, which comprises contacting the factor according to claim 329 with a non-embryonic somatic cell.

340 . The method according to claim 339 , wherein the non-embryonic somatic cell is a human cell.

341 . An induced pluripotent stem cell obtained by the method according to claim 339 .

342 . A somatic cell derived by inducing differentiation of the induced pluripotent stem cell according to claim 341 .

343 . A method for improving differentiation ability and/or growth ability of a cell, which comprises contacting the factor according to claim 329 , with the cell.

344 . The method according to claim 343 , wherein the cell is a human cell.

345 . A cell obtained by the method according to claim 343 .

346 . A somatic cell derived by inducing differentiation of the cell according to claim 345 .

347 . A factor for a somatic cell, which comprises each of the following: an Oct family polypeptide, a Klf family polypeptide, and a growth factor.

348 . The factor of claim 347 , wherein the factor is an induction factor.

349 . The factor according to claim 347 , wherein the growth factor is basic fibroblast growth factor (bFGF).

350 . The cell according to claim 341 , which is a human cell.

351 . The cell according to claim 341 , which is a mouse cell.

352 . The cell according to claim 342 , which is a human cell.

353 . The cell according to claim 342 , which is a mouse cell.

354 . The method according to claim 339 , wherein the factor comprises each of the following: an Oct family polypeptide, a Klf family polypeptide, and a Myc family polypeptide.

355 . The method according to claim 339 , wherein the factor comprises each of the following: Oct3/4, Klf4, and c-Myc polypeptides.

356 . The method according to claim 354 , wherein the factor further comprises: a Sox family polypeptide.

357 . The method according to claim 356 , wherein the factor comprises a Sox2 polypeptide.

358 . The method according to claim 339 , wherein the contacting is in the absence of eggs, embryos, or embryonic stem (ES) cells.