Figure 4

Sam68 overexpression induces apoptosis dependent on RNA binding. A. Tet-off cells conditionally expressing wild-type HA-Sam68 were cultured on coverslips in 10% serum with or without doxycycline for 24 h, fixed and stained with DAPI. B. Tet-off cell lines expressing the indicated Sam68 proteins were cultured in the presence or absence of doxycycline for 72 h and then assayed for caspase activation with a cell-permeable fluorescent caspase inhibitor, FAM-VAD-FMK (FVF). Fixed cells were counterstained prior to flow cytometry with propidium iodide (PI). Results with two different clones of cells expressing wt Sam68 are shown.