FUS and EWSR1 are RNA-binding proteins that accumulate at DNA lesions in a poly(ADP-ribose)-dependent manner. Notably, upon foci formation, both proteins are gradually excluded from sites of complex DNA damage, yet the mechanism and significance of this exclusion remain unclear. Here, we show that inhibition of the transcription-associated cyclin-dependent kinases CDK7, CDK9, and CDK12/13, or degron-mediated depletion of RPB1, the catalytic subunit of RNA polymerase II, prevents the exclusion of FUS and EWSR1. RPB1 itself is also excluded from sites of DNA damage with kinetics similar to those of FUS. Furthermore, we demonstrate that CDK7 inhibition leads to reduced 53BP1 accumulation at DNA lesions in vivo. Our findings clarify a mechanism by which RPB1 and FUS/EWSR1 are excluded from damaged chromatin and highlight its importance in DNA repair coordination.
Varhoshkova et al. (Wed,) studied this question.