RNF20 and USP44 regulate embryonic stem cell differentiation by modulating H2B monoubiquitylation

Embryonic stem cells (ESCs) maintain high genomic plasticity, essential for their capacity to enter diverse differentiation pathways. Post-transcriptional modifications of chromatin histones play a pivotal role in maintaining this plasticity. We now report that one such modification, monoubiquitylation of histone H2B on lysine 120 (H2BK120ub1), catalyzed by the E3 ligase RNF20, increases during ESC differentiation and is required for efficient execution of this process. This increase is particularly important for the transcriptional induction of long genes during ESC differentiation. Furthermore, we identify USP44 as a deubiquitinase whose downregulation by differentiation signals contributes to the increase in H2BK120ub1. Our findings suggest that optimal ESC differentiation requires dynamic changes in H2B ubiquitylation patterns, which must occur in a timely and well-coordinated manner. RNF20 depleted or control NTera2 cells stimulated with RA for 72 hours