Figure 4.

Telomere Dynamics during CiPSC Induction

(A) Morphological changes of MEFs during chemical induction under bright field with phase contrast optics or Oct4-GFP fluorescence. Compact colonies were formed at day 40 of induction by three-step method, earlier than with the BrdU method. Scale bar represents 100 μm.

(B) mRNA expression levels of Oct4, Sox2, Nanog, and Zscan4 during chemical induction.

(C) Relative expression levels of Tert and Terc during chemical induction.

(D) Telomerase activity by TRAP assay of MEFs and reprogramming cells during induction, compared with CiPSCs at P4 or P5. Lysis buffer as negative control.

(E) Telomere length distribution shown as TRF by Southern blot analysis during chemical induction (day 0–40) compared with CiPSCs. MW, molecular weight.

(F) Immunofluorescence showing co-staining of γH2AX (green) at telomeres (TRF1, red). Yellow (white arrows) in merged images indicates co-localized foci of TRF1 and γH2AX. Scale bar represents 5 μm.

(G) Quantification of TIFs. n = 100 cells counted.

Data represent mean ± SEM from three independent experiments. ^∗p < 0.05, ^∗∗p < 0.01, ^∗∗∗p < 0.001.

See also Figure S4.