Ectopic expression of Cdt2 enhances the G1 arrest response.

<p>A. Cdt1 degradation and MCM2-7 loading in control HEK293 cells and Cdt2-FLAG expressing HEK293 cells. Control (293) and Cdt2-FLAG expressing HEK293 cells (Cdt2) were arrested in M phase and released with or without UV irradiation (40 J/m²). Cells were collected at the indicated time-points to prepare whole cell extracts (WCE) and an insoluble fraction. Note that Cdt2 (both endogenous (end.) and FLAG-tagged (Cdt2-FLAG)) were hyperphosphorylated in M phase[<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0120553#pone.0120553.ref025" target="_blank">25</a>]. B. Flow cytometry analysis of Cdt2-FLAG expressing cells. Cells treated as in A were collected 24 h after release for flow cytometry. To block cells in mitosis, nocodazole was added at the 10 h time-point. Frequency of G1 phase cells was shown (%).