Figure 5.

CstF-64 is required for S-phase entry and histone expression. (A) Cell cycle analysis of WT and Cstf2^E6 ESCs mitotically synchronized (0 h) with nocodazole and subsequently released for 10 h in 2 h time points (2–10 h). Cells were stained with PI and analyzed using flow cytometry. (B) Corresponding percentages of synchronized and released WT and Cstf2^E6 ESCs in the cell cycle phases, G₁ (orange), S (blue) and G₂/M (brown). (C, D) Western blot analysis detecting the expression of CstF-64, τCstF-64, CstF-77 and the histone processing components, FLASH and SLBP in mitotically synchronized WT and Cstf2^E6 ESCs that were released for 10 h post block. Cyclin B1 expression indicates G₂/M phase transition. (E) Comparative western blot analysis of the core histone families, H2B, H3 and H4 in mitotically synchronized WT and Cstf2^E6 ESCs.