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2. After 4–7 days of culture, the cells were subjected to a first passage using a conventional trypsin method, and the suspended cells were plated in ESC maintenance medium containing 20% FBS.
IMPORTANT
(i) ESC maintenance medium consists of KnockoutTM DMEM (Life Technologies), 20% FBS, 1 × NEAA, 1 × Glutamine, 1 × Nucleosides, 10-4M 2-mercaptoethanol, and 1000 U/ml LIF.
(ii) FBS lots should be confirmed for suitability for use in the culture of mouse ES cells.
(iii) We have established multiple STAP stem cell lines from STAP cells derived from CD45+ haematopoietic cells. Of eight clones examined, none contained the rearranged TCR allele, suggesting the possibility of negative cell-type-dependent bias (including maturation of the cell of origin) for STAP cells to give rise to STAP stem cells in the conversion process. This may be relevant to the fact that STAP cell conversion was less efficient when non-neonatal cells were used as somatic cells of origin in the current protocol.
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3. Subsequent passaging was performed at a split ratio of 1:10 every second day until reaching subconfluency. We tested the following three different genetic backgrounds of mice for STAP stem-cell establishment from STAP cell clusters, and observed reproducible establishment: C57BL/6 carrying Oct4-gfp (29 of 29), 129/Sv carrying Rosa26-gfp (2 of 2), and 129/Sv × C57BL/6 carrying cag-gfp (12 of 16). STAP stem cells with all these genetic backgrounds showed chimaera-forming activity.
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FI stem cell conversion culture
1. STAP cell clusters were transferred to Fgf4-containing trophoblast stem-cell medium (Tanaka et al, Science, 1998) on MEF feeder cells in 96-well plates (Obokata, Nature, 2014b).
IMPORTANT
(i) TS medium consists of RPMI 1640 with 20% FBS, 1 mM Sodium Pyruvate, 100 µM 2-mercaptoethanol, 2 mM L-glutamine, 25 ng/ml of recombinant FGF4, and 1 µg/ml of heparin.
(ii) Different lots of FBS may results in significant differences in the behavior of cultured cells.
2. In most cases (40 of 50 experiments), colonies grew in 10–50% of wells in 96-well plates. In a minority of cases (10 of 50 experiments), no colony growth was observed and/or only fibroblast-like cells appeared.
IMPORTANT
(i) The cells in proliferative colonies also appear similar to fibroblasts, but gradually change morphology, coming to resemble epithelial cells.
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3. The cells were subjected to the first passage during days 7–10 using a conventional trypsin method. Subsequent passages were performed at a split ratio of 1:4 every third day before they reached subconfluency.
IMPORTANT
The cells must not be dissociated completely. Partial dissociation is optimal to maintain viability and self-renewal, as seen in the case of embryo-derived trophoblast stem cells.
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References
Obokata, H. et al.Obokata. Stimulus-triggered fate conversion of somatic cells into pluripotency, Nature, 505, 641-647 (2014a)
Obokata, H. et al. Bidirectional developmental potential in reprogrammed cells with acquired pluripotency. 676–680 (2014b)
Ohbo, K. et al. Identification and characterization of stem cells in prepubertal spermatogenesis in mice small star, filled. Dev. Biol. 258, 209–225 (2003)
Yoshimizu, T. et al. Germline-specific expression of the Oct4/green fluorescent protein (GFP) transgene in mice. Dev. Growth. Differ. 6, 675-684 (1999)
Ogawa, K., Matsui, H., Ohtsuka, S. & Niwa, H. A novel mechanism for regulating clonal propagation of mouse ES cells. Genes Cells 9, 471–477 (2004)
Tanaka, S., Kunath, T., Hadjantonakis, A. K., Nagy, A. & Rossant, J. Promotion of trophoblast stem cell proliferation by FGF4. Science 282, 2072–2075 (1998)
＜参照＞
Obokata, H. et al.Obokata. 『体細胞の多能性への刺激惹起性運命変換』Nature, 505, 641-647 (2014a)
Obokata, H. et al. 『取得多能性を持つ再プログラム細胞における双方向への発生能力』 676–680 (2014b)
Ohbo, K. et al. 『マウスの小さな星の中に満たされた思春期前の精子形成における幹細胞の同定と特徴づけ』 Dev. Biol. 258, 209–225 (2003)
Yoshimizu, T. et al. 『マウスのOct4/緑色蛍光タンパク質（GFP）導入遺伝子の生殖細胞特異的発現』 Dev. Growth. Differ. 6, 675-684 (1999)
Ogawa, K., Matsui, H., Ohtsuka, S. & Niwa, H. 『マウスES細胞のクローン増殖を調節するための新しいメカニズム』 Genes Cells 9, 471–477 (2004)
Tanaka, S., Kunath, T., Hadjantonakis, A. K., Nagy, A. & Rossant, J. 『FGF4＜線維芽細胞増殖因子＞によるＴＳ細胞増殖の推進』 Science 282, 2072–2075 (1998)
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Associated Publications
This protocol is related to the following articles:
Stimulus-triggered fate conversion of somatic cells into pluripotency
Haruko Obokata, Teruhiko Wakayama, Yoshiki Sasai, Koji Kojima, Martin P. Vacanti, Hitoshi Niwa, Masayuki Yamato, and Charles A. Vacanti
Journal title
Nature
Vol.
505
Issue
-7485
Pages
641 - 647
Publication date
29/01/2014
DOI:
doi:10.1038/nature12968
＜関連著作物＞
このプロトコルは下記論文に関連している。
『体細胞の多能性への刺激惹起性運命変換』
Haruko Obokata, Teruhiko Wakayama, Yoshiki Sasai, Koji Kojima, Martin P. Vacanti, Hitoshi Niwa, Masayuki Yamato, and Charles A. Vacanti
Journal title
Nature
Vol.
505
Issue
-7485
Pages
641 - 647
Publication date
29/01/2014
DOI:
doi:10.1038/nature12969
