第一話 Past background of STAP [Findings]
[Findings（発見）]
「発見」
[(Reference: a briefing narrated by H.Obokata in the international press conference held by Nature on 28th January, 2014)]
「参照：２０１４年１月２８日 Natureによって開催された記者会見において、H.Obokataによって述べられた簡潔なまとめである。」
[Our main findings reported in STAP papers were as follows.]
「STAP論文で報告された、我々の主な発見は、次のようなものである。」
[When ordinary somatic cells, such as lymphocytes from newborn mice, were shocked with a dose of sublethal stress,
such as low pH or mechanical force,
they were stripped of their differentiation memory,
and reverted to a state of pluripotency that, in many ways, resembled what is seen in ES cells.]
「通常の体細胞は、たとえば新生仔マウスのリンパ球は、致死量以下のストレス、たとえば低いphや機械的な力、によってショックを受け、それらの分化記憶は削除され、その結果、多能性を持った段階に戻り、多くの点で、それはES細胞において観察される状態と似たものであった。」
[ We named this conversion process STAP, which stands for Stimulus-Triggered Acquisition of Pluripotency,and the cells resulting from this process, we called STAP cells. ]
「我々は、この転換プロセスをSTAPと名づけたのだが、このSTAPとはStimulus-Triggered Acquisition of Pluripotencyを意味し、この転換プロセスの結果できた細胞を、STAP細胞と呼ぶ。」
[STAP cells showed all the hallmarks of pluripotency, and could contribute to chimeric mice and
germline transmission when injected into early-stage embryos. ]
「STAP細胞は多能性の全ての特徴を示し、これによってキメラマウスを作成でき、初期胚に注射することでジャームライントランスミッションを可能にする。」
[It was really surprising to see that such a remarkable transformation could be triggered simply by stimuli from outside of the cell.]
「そのような目を見張るトランスフォーメーションが、細胞外からの刺激のみによって引き起こされることは、驚くべきことである。」
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We also found the culture conditions in which STAP cells could be robustly expanded as stem cell lines. In fact, STAP cells showed an intriguing difference from ES cells and iPS cells. When injected into mouse blastocysts, both ES cells and iPS cells can differentiate into somatic cells of the fetus, but they cannot form placenta. In contrast, STAP cells could contribute to both the somatic cells and the placenta, suggesting that STAP cells might represent an even more immature state.
Two types of stem cell lines were established from STAP cells. One was called STAP stem cells which were subcultured in ES medium. The character of STAP stem cells was quite similar to both ES cells and iPS cells. When injected in to mouse blastocysts, STAP stem cells could contribute only to fetuses. Another was called FI (FGF4-Induced) stem cells. When cultured in TS (trophoblast stem) cell medium, STAP cells also obtained a strong proliferative potential. These cells took over the unique characters of STAP cells, and were able to contribute not only to fetuses but also placentas as well as STAP cells.
