Molecular Basis for the PZP Domain of BRPF1 Association with Chromatin

Abstract

The assembly of human histone acetyltransferase MOZ/MORF complexes relies on the scaffolding bromodomain plant homeodomain (PHD) finger 1 (BRPF1) subunit. The PHD-zinc-knuckle-PHD module of BRPF1 (BRPF1_PZP) has been shown to associate with the histone H3 tail and DNA; however, the molecular mechanism underlying recognition of H3 and the relationship between the histone and DNA-binding activities remain unclear. In this study, we report the crystal structure of BRPF1_PZP bound to the H3 tail and characterize the role of the bipartite interaction in the engagement of BRPF1_PZP with the nucleosome core particle (NCP). We find that although both interactions of BRPF1_PZP with the H3 tail and DNA are required for tight binding to NCP and for acetyltransferase function of the BRPF1-MORF-ING5-MEAF6 complex, binding to extranucleosomal DNA dominates. Our findings suggest that functionally active BRPF1_PZP might be important in stabilization of the MOZ/MORF complexes at chromatin with accessible DNA.

Keywords: BRPF1; DNA; MORF; MOZ; PZP; chromatin; histone.