Recognition of ubiquitinated nucleosomes. (February 2017)

• Record Type: Journal Article
• Authors: Morgan, Michael T; Wolberger, Cynthia
• Is Part Of: Current opinion in structural biology. Volume 42(2017)
• Page Start: 75
• Page End: 82
• Publication Date: 2017-02
• Subjects: Molecular biology -- Periodicals; 570
• DOI: 10.1016/j.sbi.2016.11.016
• Languages: English
• ISSNs: 0959-440X

Abstract

Highlights: New advances have made it possible to determine structure of complexes containing ubiquitinated nucleosomes. X-ray crystallographic and EM studies shed light on how the SAGA complex engages nucleosomes containing monoubiquitinated H2B. The intact SAGA complex adopts multiple discrete conformations. An EM study shows how 53BP1 recognizes tandem ubiquitin and methyl marks in the nucleosome. Abstract : Histone ubiquitination plays a non-degradative role in regulating transcription and the DNA damage response. A mechanistic understanding of this chromatin modification has lagged that of small histone modifications because of the technical challenges in preparing ubiquitinated nucleosomes. The recent structure of the DUB module of the SAGA coactivator complex bound to a nucleosome containing monoubiquitinated H2B has provided the first view of how specialized subunits target this enzyme to its substrate. Single particle electron microscopy of the intact SAGA coactivator suggests how the DUB module and histone acetyltransferase module engage a nucleosomal substrate. A cryo EM study of 53BP1 bound to nucleosomes containing ubiquitinated H2A and H4 methylated at K20 extends our understanding of recognition of biologically distinct combinations of chromatin marks through multivalent interactions.