Biology Seminar - Cynthia Wolberger

Abstract:

Post-translational modifications of histones play a central role in regulating all cellular processes requiring access to DNA. Monoubiquitinated histone H2B-K120 is a hallmark of actively transcribed genes that plays multiple roles in activating transcription, while monoubiquitinated histone H2A-K119 is abundant in heterochromatin, which is transcriptionally silent. Our structural studies have revealed how H2B is specifically ubiquitinated and deubiquitinated, as well as the mechanism by which H2B ubiquitination regulates access to the nucleosome acidic patch, a hotspot for interactions with other chromatin-modifying enzymes. I will also discuss recent progress in studies of a histone kinase that has an unusual way of binding nucleosomes.