LSD1 promotes H2A/H2A.X ubiquitylation upon DNA damage. (a) 293T cells were infected with control or LSD1-specific shRNA, and then Western blotted with the indicated antibodies. (b and c) Cells from panel a were synchronized in late G2 using thymidine-nocodazole and were harvested 4 h after the indicated doses of γ-IR. Whole cell extracts were analyzed by Western blot using the indicated antibodies. (d) After knockdown and selection, U2OS cells were irradiated and processed for immunofluorescence using antibodies against MDC1 and ubiquitylated H2A. (e) Quantitation of panel d. (f) U2OS cells treated with control or LSD1-specific shRNA were laser microirradiated and stained with the indicated antibodies. (g) Quantitation of panel f. Bars, 20 µm.