Induction of Pluripotent Stem Cells from Mouse Embryonic and Adult Fibroblast Cultures by Defined Factors
Cell, 2006 · paper · Biomedicine
Shows that introducing four factors (Oct3/4, Sox2, c-Myc and Klf4) into mouse embryonic or adult fibroblasts produces induced pluripotent stem cells. These resemble embryonic stem cells and can form tissues of all three germ layers.
Checked: PDF from repository.kulib.kyoto-u.ac.jp, fetched 5 Oct 2026. Page numbers are those of that PDF.
3 findings
Reference or label Figure 4 legend: "expression compared to median levels of the eight samples", but the legend lists nine samples and the heat maps have nine labelled columns.
- p. 6 Figure 4 legend, panel A
expression compared to median levels of the eight samples
- p. 6 Figure 4A/4B column labels
ES, iPS-MEF4-7, iPS-MEF10-6, iPS-MEF3-2, iPS-MEF3-3, MEF, MEF+4factors, MEF+KRasV12, 3T3+HRasV12
- p. 6 Figure 4 legend (A)
median levels of the eight samples
Judge's note: Viewed page 6. Column labels in both panels: ES, iPS-MEF4-7, iPS-MEF10-6, iPS-MEF3-2, iPS-MEF3-3, MEF, MEF+4factors, MEF+KRasV12, 3T3+HRasV12, which is nine. The legend lists the same nine and then says 'the eight samples'. Nothing in the legend or the DNA Microarray methods says a sample was left out of the median.
Second check: another model agreed
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Reference or label Figure 6D legend: "Cells were counterstained with eosin (blue)." The dye name and the stated colour do not match; the panels show a blue nuclear counterstain.
- p. 8 Figure 6 legend, panel D
Cells were counterstained with eosin (blue).
Only the authors can say what is right here.
Judge's note: Rests on outside knowledge: eosin is a pink/red dye and a blue nuclear counterstain is typically hematoxylin. Viewed page 8: the legend reads as quoted and the 6D panels show brown signal on blue nuclei with no pink. The Methods name hematoxylin and eosin only for teratoma sections. The authors should say which counterstain was used.
Second check: another model agreed
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Wording Figure 7B protein panels mark several bars with "**", but the legend defines only "*p < 0.05 compared to undifferentiated cells."
- p. 11 Figure 7 legend (continued), panel B
*p < 0.05 compared to undifferentiated cells.
- p. 10 Figure 7B protein panels (Oct3/4, Sox2, Nanog)
**
Only the authors can say what is right here.
Judge's note: Viewed page 10: '**' appears over TTFgfp4-3 D and ES D in the Oct3/4 protein panel and over ES D in the Sox2 and Nanog panels. The legend continuation on page 11 defines only the single asterisk. The Figure 3 legend defines '**p < 0.01', but for a different test (ANOVA with Scheffe for ChIP, against Student's t test for protein levels), so the meaning in Figure 7 is not stated.
Second check: another model agreed
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3 minor (typos and the like; most checked by the judge only)
Typo Discussion: "obtained an iPS clone (TTF4gfp4-7)"; the loxP-flanked clone is named iPS-TTFgfp4 (clone 7) / TTFgfp4-7 everywhere else.
- p. 11 Discussion, left column, last lines
an iPS clone (TTF4gfp4-7)
- p. 7 Results, TTF paragraph
another iPS-TTFgfp4 (clone 7), in which the cDNA for each of the four factors was flanked with two loxP sites
- p. 7 Results, TTF paragraph
another iPS-TTFgfp4 (clone 7), in which the cDNA for
- p. 11 Discussion, loxP paragraph
obtained an iPS clone (TTF4gfp4-7)
Judge's note: Viewed page 11: 'TTF4gfp4-7' is printed. Page 7 Results calls it 'another iPS-TTFgfp4 (clone 7), in which the cDNA for each of the four factors was flanked with two loxP sites'; the Figure 6C and Figure 7A/7C labels use TTFgfp4-7. No clone named TTF4gfp4 is defined, so the extra '4' is a typo.
Second check: none (judge only)
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Typo Two sentences in the same paragraph begin with 'Finally': "Finally, we found that iPS cells could not remain undifferentiated…" and "Finally, subclones of iPS cells were positive for alkaline phosphatase…".
- p. 9 Results, last paragraph
Finally, subclones of iPS cells were pos-
Judge's note: Viewed page 9, left column. Both sentences are there, separated by one sentence ('These results, together with…'), so they are not strictly consecutive. A repeated discourse marker; cosmetic only.
Second check: none (judge only)
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Typo Figure 7B legend: "or induced to differentiated in vitro through embryoid body formation (D)"; should read "induced to differentiate".
- p. 10 Figure 7 legend, panel B
or induced to differentiated in vitro through embryoid body formation (D)
- p. 10 Figure 7 legend (B)
induced to differentiated in vitro
Judge's note: Viewed the page 10 image; the legend prints 'induced to differentiated'. Grammar slip in the published page, not an extraction artefact.
Second check: none (judge only)