Figure 5. Effects of β-TRCP-mediated degradation of Set8 on cell growth.

(a) U2OS cells with induced Flag-Set8^WT, Set8^ΔPIP, Set8^S253A or Set8^ΔPIP/S253A were treated with different doses of UVC (0–50 J m⁻²) for 10 min before whole cell lysates (WCL) were collected for immunoblot (IB) analysis to monitor the changes in Flag-Set8 abundance. (b) Quantification of the Flag-Set8 band intensities in a. Set8 band intensity was normalized to vinculin. (c) IB analysis of WCL from U2OS cells infected with lentivired shRNAs specific for GFP or β-TRCP1, treated with UVC (10 J m⁻²) and collected at indicated time points. (d–f) U2OS cells harbouring Flag-Set8^WT, Set8^ΔPIP, Set8^S253A or Set8^ΔPIP/S253A were cultured in the absence or presence of 0.1 μg ml⁻¹ doxycycline (Dox). The total cell numbers at the different days were plotted (d). Clonogenic assay (e) and soft agar assay (f) were used to measure cell proliferation. Data are shown as mean±s.d. of three independent experiments. *P<0.05, Student's t-test.