Putting the brakes on transcription at damaged chromatin: Do Polycomb silencers do more than modify histones?

One of the cellular responses to DNA damage is to monitor and execute temporary arrest of RNA synthesis at chromatin lesions. The Polycomb silencer BMI1 is a well-known contributor to this process. We recently described a new mode of BMI1-mediated transcription arrest at lesions that involves UBR5 E3 ligase and FACT histone chaperon.