Chromatin structure and its chemical modifications regulate the ubiquitin ligase substrate selectivity of UHRF1

• DOI: 10.1073/pnas.1806373115
• Publication Date: 2018-08-13T19:10:09Z
• Authors: Robert M. Vaughan; Bradley M. Dickson; Matthew F. Whelihan; Andrea L. Johnstone; Evan M. Cornett; Marcus A. Cheek; Christine A. Aush...; Martis W. Cowles; Zu-Wen Sun; Scott B. Rothbart
• Keywords: Epigenomics; Crosstalk

Mitotic inheritance of DNA methylation patterns is facilitated by UHRF1, a DNA- and histone-binding E3 ubiquitin ligase that helps recruit the maintenance methyltransferase DNMT1 to replicating chromatin. The function UHRF1 dependent on its ability bind chromatin, where it facilitates monoubiquitination histone H3 at lysines 18 23, docking site for DNMT1. Because technical limitations, this model UHRF1-dependent has been constructed largely based genetics biochemical observations querying methylated oligonucleotides, synthetic peptides, heterogeneous chromatin extracted from cells. Here, we construct semisynthetic mononucleosomes harboring defined modifications perform rigorous analysis binding enzymatic activity with these reagents. We show multivalent engagement nucleosomal linker dimethylated lysine 9 directs toward substrates. Notably, reveal molecular switch, stimulated recognition hemimethylated DNA, which redirects away histones in favor robust autoubiquitination. Our studies support noncompetitive recruitment define role as regulator substrate selectivity.