Producing primate embryonic stem cells by somatic cell nuclear transfer

1
???????
2
(No Transcript)
3
Producing primate embryonic stem cells by somatic
cell nuclear transfer
4
(No Transcript)
5
???????

• ????
• ??????????????????????????
• ????????
• ?????????
• ???????????????????????????????????????????
• 2006??????????(Shinya Yamanaka)
  ???????Oct4?Sox2?c-Myc?Klf4???????????????
• ????????????????????

6
(No Transcript)
7
(No Transcript)
8
In vitro reprogramming of fibroblasts into a
pluripotent ES-cell-like state

• Nuclear transplantation can reprogramme a somatic
  genome back into an embryonic epigenetic state,
  and the reprogrammed nucleus can create a cloned
  animal or produce pluripotent embryonic stem
  cells. One potential use of the nuclear cloning
  approach is the derivation of 'customized'
  embryonic stem (ES) cells for patient-specific
  cell treatment, but technical and ethical
  considerations impede the therapeutic application
  of this technology. Reprogramming of fibroblasts
  to a pluripotent state can be induced in vitro
  through ectopic expression of the four
  transcription factors Oct4 (also called Oct3/4 or
  Pou5f1), Sox2, c-Myc and Klf4. Here we show that
  DNA methylation, gene expression and chromatin
  state of such induced reprogrammed stem cells are
  similar to those of ES cells. Notably, the
  cellsderived from mouse fibroblastscan form
  viable chimaeras, can contribute to the germ line
  and can generate live late-term embryos when
  injected into tetraploid blastocysts. Our results
  show that the biological potency and epigenetic
  state of in-vitro-reprogrammed induced
  pluripotent stem cells are indistinguishable from
  those of ES cells.

9
(No Transcript)
10
(No Transcript)
11
(No Transcript)
12

• Successful reprogramming of differentiated human
  somatic cells into a pluripotent state would
  allow creation of patient- and disease-specific
  stem cells. We previously reported generation of
  induced pluripotent stem (iPS) cells, capable of
  germline transmission, from mouse somatic cells
  by transduction of four defined transcription
  factors. Here, we demonstrate the generation of
  iPS cells from adult human dermal fibroblasts
  with the same four factors Oct3/4, Sox2, Klf4,
  and c-Myc. Human iPS cells were similar to human
  embryonic stem (ES) cells in morphology,
  proliferation, surface antigens, gene expression,
  epigenetic status of pluripotent cell-specific
  genes, and telomerase activity. Furthermore,
  these cells could differentiate into cell types
  of the three germ layers in vitro and in
  teratomas. These findings demonstrate that iPS
  cells can be generated from adult human
  fibroblasts.

13
(No Transcript)
14

• Somatic CELL nuclear transfer allows trans-acting
  factors present in the mammalian oocyte to
  reprogram somatic CELL nuclei to an
  undifferentiated state. Here we show that four
  factors (OCT4, SOX2, NANOG, and LIN28) are
  sufficient to reprogram human somatic CELLs to
  pluripotent STEM CELLs that exhibit the essential
  characteristics of embryonic STEM CELLs. These
  human induced pluripotent STEM CELLs have normal
  karyotypes, express telomerase activity, express
  CELL surface markers and genes that characterize
  human ES CELLs, and maintain the developmental
  potential to differentiate into advanced
  derivatives of all three primary germ layers.
  Such human induced pluripotent CELL lines should
  be useful in the production of new disease models
  and in drug development as well as application in
  transplantation medicine once technical
  limitations (for example, mutation through viral
  integration) are eliminated.