SMARCA4 and cancer: To check if poly-ADP-ribosylation of BRG1 directly conditioned BRG1 activity and BRG1-dependent transcription, we tested the impact of the PARP1 inhibitor on the transcription of genes that are over-expressed in cancer cells and characterized by the occurrence of PARP1 and BRG1 at their promoters, but without considerable nucleosome acetylation (Figure 4D and Table S2).