Human USP3 Is a Chromatin Modifier Required for S Phase Progression and Genome Stability

Abstract

Protein ubiquitination is critical for numerous cellular functions, including DNA damage response pathways [1, 2]. Histones are the most abundant monoubiquitin conjugates in mammalian cells; however, the regulation and the function of monoubiquitinated H2A (uH2A) and H2B (uH2B) remain poorly understood. In particular, little is known about mammalian deubiquitinating enzymes (DUBs) that catalyze the removal of ubiquitin from uH2A/uH2B. Here we identify the ubiquitin-specific protease 3 USP3 as a deubiquitinating enzyme for uH2A and uH2B. USP3 dynamically associates with chromatin and deubiquitinates H2A/H2B in vivo. The ZnF-UBP domain of USP3 mediates uH2A-USP3 interaction. Functional ablatio..