Figure 3. Zfp281 is Critical for Primed Pluripotency. See also Figure S3.
(A) Proliferation analysis of WT and Zfp281 KO ESCs cultured in SL, 2iL or FA. Error bars indicate average ± SEM (n=3).
(B) Colony formation assay for WT and Zfp281 KO ESCs. Colonies were stained for alkaline phosphatase (AP) activity at day 6 of culture in specified conditions, and positive colonies were scored into three categories (compact, mixed and diffuse as indicated). Error bars indicate average ± SEM (n=6). Student's unpaired t test (***P<0.001, **P<0.01) relative to WT ESCs was performed.
(C) Immunostaining of Nanog and Oct4 at day 8 under FA. Scale bars represent 100 μm.
(D) Representative bright-field images at day 6 of Zfp281 KD (shZfp281) EpiSCs and rescued (+R) line compared with control luciferase knockdown (shLuci) EpiSCs.
(E) Zfp281 KD facilitates reprogramming of EpiSCs towards naive-like cells (Epi-iPSCs). Two different EpiSC lines were transfected with three independent shRNAs against Zfp281, and Epi-iPSC colony numbers were quantified at day 6 in 2iL. Error bars indicate average ± SEM (n=3). Student's unpaired t test (***P<0.001) relative to shLuci was performed.
(F) Contribution of Epi-iPSCs to the germline (top) and chimeric E13.5 mouse embryos (bottom). Epi-iPSCs were generated by reprogramming EpiSCs with pTRIPZ-shZfp281. EpiiPSCs were labeled with a Tomato reporter transgene and maintained without Dox (OFF).
(G) ZNF281 dependency of conventional hESCs. Representative colony morphology under bright-field (top) and fluorescent (for OCT4-GFP; middle) microscope as well as AP-stained colonies (bottom) are shown. ZNF281-depleted and control shLuci O4G hESCs were passaged twice in primed culture conditions before microscopy.
(H) A strategy to test effects of ZNF281 depletion on converting primed hESCs to a naive state using the published 5iL condition.
(I) Quantification of AP-positive colony numbers of hESCs at day 10 of primed human ES medium (FA) or naive culture conditions (5iL) upon control or ZNF281 KD. Error bars indicate average ± SEM (n=3). Student's unpaired t test (***P<0.001, **P<0.01) relative to shLuci hESCs.