Figure2-bは若山さん以外には誰も作れていないことになってる。STAP細胞は
Oct4を発現するんだけどFGF4誘導されたFI幹細胞もわずかにOct4遺伝子を発現しているんだね。
TS細胞はそれがないので全くTS様になったわけではないんだな。
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Despite their similarities, we noted that Fgf4-induced stem cells also possessed some critical differences compared with blastocyst-derived trophoblast stem cells. First, Fgf4-induced stem cells exhibited moderate GFP signals and expressed a moderate level of Oct4 (Fig. 2b; moderate and low levels of immunostaining signals were also seen for Oct4 and Nanog proteins, respectively; Extended Data Fig. 2c), unlike conventional trophoblast stem cells that have little Oct4 expression (Fig. 2e). Second, unlike trophoblast stem cells, blastocyst-injected Fgf4-induced stem cells also contributed to embryonic tissues (in all cases that involved chimaeric placentae; n = 32), although the extent of contribution was generally modest (Fig. 2g).
それらの類似性にもかかわらず、我々はFgf4誘導幹細胞は、胚盤胞由来栄養膜幹細胞と比較していくつかの重要な違いを持っていたことを指摘した。第一に、従来の栄養膜幹細胞がOct4蛋白発現が皆無であるのに対して(図2e)、Fgf4誘導幹細胞は適度なGFPシグナルを示し、そして適度なレベルOct4蛋白を発現した（図2b;中程程度および低いレベルで免疫染色シグナルが、それぞれ、Oct4とNanog蛋白質について見られた;拡張データ図2c）。第二に、栄養膜幹細胞とは異なり、胚盤胞に注入したFgf4誘導幹細胞は、寄与の程度は、一般的に控えめではあるものの（図2g）、胚組織にも寄与した（キメラ胎盤を含むすべてのケースにおいて;n = 32）、
ウィキのInner cell massに以下のような解説がある。
(*ttps://en.wikipedia.org/wiki/Inner_cell_mass)
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The physical and functional separation of the inner cell mass from the trophectoderm (TE) is a special feature of mammalian development and is the first cell lineage specification in these embryos. Following fertilization in the oviduct, the mammalian embryo undergoes a relatively slow round of cleavages to produce an eight cell morula. Each cell of the morula, called a blastomere, increases surface contact with its neighbors in a process called compaction. This results in a polarization of the cells within the morula, and further cleavage yields a blastocyst of roughly 32 cells.[1] In mice, about 12 internal cells comprise the new inner cell mass and 20 – 24 cells comprise the surrounding trophectoderm.[2][3] There is variation between species of mammals as to number of cells at compaction with bovine embryos showing differences related to compaction as early as 9-15 cells and in rabbits not until after 32 cells.[4] There is also interspecies variation in gene expression patterns in early embryos.[5]
In mice, about 12 internal cells comprise the new inner cell mass and
20 – 24 cells comprise the surrounding trophectoderm.[2][3] とあるところ、
32細胞期を既に初期胚盤胞としているね。
ここの説明ではコンパクションは8細胞期で起きると書かれている。
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Following fertilization in the oviduct, the mammalian embryo undergoes a relatively slow round of cleavages to produce an eight cell morula. Each cell of the morula, called a blastomere, increases surface contact with its neighbors in a process called compaction.
その件に関しては論文は以下のように書かれているのよ。
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Despite their similarities, we noted that Fgf4-induced stem cells also possessed some critical differences compared with blastocyst-derived trophoblast stem cells. First, Fgf4-induced stem cells exhibited moderate GFP signals and expressed a moderate level of Oct4 (Fig. 2b; moderate and low levels of immunostaining signals were also seen for Oct4 and Nanog proteins, respectively; Extended Data Fig. 2c), unlike conventional trophoblast stem cells that have little Oct4 expression (Fig. 2e). Second, unlike trophoblast stem cells, blastocyst-injected Fgf4-induced stem cells also contributed to embryonic tissues (in all cases that involved chimaeric placentae; n = 32), although the extent of contribution was generally modest (Fig. 2g).
論文上の理由ははっきり書かれてはいるのね。
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However, as Fgf4-induced stem cells lay between STAP stem cells and trophoblast stem cells in the dendrogram, the possibility of contamination of STAP stem cells in the Fgf4-induced stem-cell population cannot be ruled out.
先にe,fのリジェンドを見て置いたら?
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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). 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).
<BFP-transfected Oct4-GFP ES cells>の説明があるね。
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Oct4-GFP ES cells that constitutively expressed BFP (the number of plated cells was one-tenth of that of plated Fgf4-induced stem cells)
