Fig. 5.
Hes1 oscillation in cell cycles. (A) Comparison of growth curves. Cells that express Hes1 protein persistently and cells that lose Hes1 activity do not proliferate extensively, compared with the control, where Hes1 expression oscillates. (B) Regulation of cell cycle regulators by Hes1. Expression was examined by real-time PCR. Both sustained Hes1 expression (+Hes1) and knockdown of Hes1 activities (+dnHes1) increase expression of p21 and p27, G1 phase genes, compared with oscillatory Hes1 expression (control). Transfected cells with the control vector and nontransfected cells gave the same results (data not shown). (C) Expression of cyclin D1, a G1-specific marker. Both Hes1 and dnHes1 increase cyclin D1 expression, compared with control. All values are the average of three independent experiments with SE.