Functional Interplay between Histone H2B ADP-Ribosylation and Phosphorylation Controls Adipogenesis

Although ADP-ribosylation of histones by PARP-1 has been linked to genotoxic stress responses, its role in physiological processes has remained elusive. We found that ADPribosylation of histone H2B-Glu35 inhibits the differentiation of adipocyte precursors, leading to a reduction of newly formed adipocytes in white adipose tissue. ADP-ribosylation of Glu35 by PARP-1 inhibits phosphorylation of adjacent H2B-Ser36, which is required for the proadipogenic gene expression program. It also inhibits adipogenesis in cultured cells and a mouse lineage tracing genetic model. The activity of PARP-1 on H2B requires NMNAT-1, a nuclear NAD+ synthase, which serves as a specificity factor to direct PARP-1 catalytic activity to Glu and Asp residues. Collectively, our results demonstrate a functional interplay between H2B-Glu35 ADP-ribosylation and H2B-Ser36 phosphorylation that controls adipogenesis and cancer cell proliferation. Overall design: Using RNA-seq in 3T3-L1 cells ectopically expressing Wt or mutant histone H2B during a time course of differentiation.