Figure 2. PPM1D mRNA translation but not mRNA stability is regulated by RBM38.
(A) p53−/−HCT116 cells were uninduced (−) or induced (+) to express RBM38 for 24 hours. Total RNAs were purified and used to measure the levels of PPM1D, RBM38, p21 and actin transcripts by semi-quantitative RT-PCR. (B) Total RNAs were purified from p53−/−HCT116 cells transfected with scrambled siRNA or siRNA against RBM38 for 3 days. The levels of PPM1D, RBM38, p21 and actin transcripts were measured by semi-quantitative RT-PCR. (C) Total RNAs were purified from primary p53−/− and p53−/−; RBM38−/− MEFs and used to measure the levels of PPM1D, RBM38 and actin transcripts by semi-quantitative RT-PCR. (D) MCF7 cells were uninduced or induced to express RBM38 for 24 h and then 35S-labeled for 10 min, followed by immunoprecipitation with anti-PPM1D. The immunocomplexes were resolved by SDS-PAGE, and 35S-labeled PPM1D was visualized by autoradiography. (E) The experiment was performed as in (D) with MCF7 cells uninduced or induced to knock down RBM38 for 3 d. (F) The experiment was performed as in (D) with H1299 cells transiently transfected with a control or RBM38 siRNA for 3 days.