Figure 5.

Clock silencing accelerated cell death in mESCs. (A) Apoptosis and overall cell death of the wild type and Clock-/- mESCs were analyzed by flow cytometry using the Annexin V and PI assay, respectively. Clock-/- mESCs exhibited increased apoptosis and overall cell death. (B) Percentage of apoptotic (Annexin V) and dead (PI) cells calculated from six independent experiments. Data were expressed as means ± S.D. (C) Relative mRNA expression levels of apoptosis-related genes Bax, Bcl-2, cleaved caspase-3, and caspase-9 in wild type and Clock-/- mESCs. The mRNA expression levels were normalized to that of the endogenous GAPDH. Data represent the average of three independent experiments and are expressed as means ± S.D. Statistical significance was calculated using the Student’s t-test: * denotes P < 0.05, ** denotes P < 0.01, *** denotes P < 0.001 compared with the Ctrl group, ns, not significant