Regulation of the RNAPII Pool Is Integral to the DNA Damage Response [RNA-seq]

In response to transcription-blocking DNA damage, cells orchestrate a multi-pronged reaction, involving transcription-coupled DNA repair, degradation of RNAPII and genome-wide transcription shutdown. How these responses are connected has remained unclear. Here we show that damage-induced ubiquitylation of RNAPII itself, at a single lysine (RPB1 K1268), is the focal point for DNA damage response coordination. K1268-ubiquitylation affects DNA repair and signals RNAPII degradation, essential for surviving genotoxic insult. It is also crucial for transcriptional shutdown, in the absence of which cells display dramatic transcriptome alterations. Additionally, regulation of RNAPII stability is central to transcription recovery – indeed, depletion of the RNAPII pool underlies the failure of this process in Cockayne syndrome B cells. These data expose regulation of global RNAPII levels as integral to the cellular DNA damage response, and open the intriguing possibility that RNAPII pool size generally affects cell-specific transcription programmes, in genome instability disorders and even normal cells.