[学さんへの返事10]
(続き)
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The authors suggest that STAP cell-derived TS-like cells are distinct from embryo-derived TS cells, but the data for this are not decisive and could be attributed to persistent contamination with STAP cells or ES cells (which could expain the occasional Nanog positive cells).
いや、今送ってきたよ。
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[培地の違い1]
>>学さん
前回の続きです、まず以下はレター論文の最後の二つの文章です。
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As for STAP-cell-derived Fgf4-induced stem cells, which can also contribute to both embryonic and placental tissues, our in vitro conversion study combined with inhibitor treatments clearly indicate that the bidirectional potential of Fgf4-induced stem cells is unlikely to reflect the co-presence of separate subpopulations of ES-like and trophoblast-stem-like cells in the culture.
[培地の違い2]
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Collectively, our study indicates that STAP-based conversion can reprogram somatic cells to acquire not only pluripotency but also the ability of trophoblast differentiation.
[培地の違い4]
それに対して、Extended Data Figure 5-c,dの培地は何なのか。リジェンドには以下のようにある。
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a–f, JAK inhibitor treatment assay for Fgf4-induced stem cells. Fgf4-induced stem cells were cultured under feeder-free conditions and treated with 0.6 μM JAK inhibitor for 48 h. JAK inhibitor treatment assay eliminated ES cells (Oct4-GFP+) from the culture (a, b).
[培地の違い5]
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The level of Oct4-GFP expression in Fgf4-induced stem cells, which was moderate, was maintained even after JAK inhibitor treatment (c, d; three independent experiments). Scale bar, 100 μm.
[培地の違い7]
ではe,fの培地は何なんでしょうかね。リジェンドは以下です。
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e, f, For an additional control, Fgf4-induced stem cells were plated in trophoblast stem-cell medium containing Fgf4 together with Oct4-GFP ES cells that constitutively expressed BFP (the number of plated cells was one-tenth of that of plated Fgf4-induced stem cells).
[培地の違い8]
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Whereas BFP-expressing colonies (ES-cell-derived) still expressed Oct4-GFP in trophoblast stem-cell culture medium after 2 days (e), no Oct4-GFP+ colonies from BFP-expressing ES cells were observed in the JAK-inhibitor-treated culture (f).
[培地の違い11]
Extended Data Figure 5-cのFI-SCのOct4-GFPが蛍光しているのに、5-eのOct4-GFPが蛍光していないのは、前者の培地がES培地であり、後者の培地がTS培地だからだということです。前者は査読者の求めに応じて、まずES-like転換後のFI-SCにJAKiを添加してES細胞でないことを示したもの。後者は、TS培地の中でTS-like転換されているFI-SCのOct4-GFP蛍光がなく、混ぜているES細胞ではOct4-GFP蛍光があり、JAKi添加後では消えるという違いを示しているものです。
[培地の違い12]
論文のリジェンドの説明では培地の違いが分かりにくいですね。ど素人には理解しにくい。でも、本文の説明をよく読めば、 <our in vitro conversion study combined with inhibitor treatments clearly indicate that the bidirectional potential of Fgf4-induced stem cells is unlikely to reflect the co-presence of separate subpopulations of ES-like and trophoblast-stem-like cells in the culture. >の実験ってExtended Data Figure 5-e,fの実験では無いかと気づけますね。
デイナの記事はそこに繋がっているのね。
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“The bar to say you’ve demonstrated your hypothesis is correct is very high for those journals,” Vacanti says. “It’s a lower bar for other journals. Do you decide to try to jump over a lower bar or do you jump higher?”
