Direct Bre1-Paf1 complex interactions and RING finger-independent Bre1-Rad6 interactions mediate histone H2B ubiquitylation in yeast.

ABSTRACT: Recent yeast genetic studies have implicated the ubiquitin-conjugating enzyme and ubiquitin ligase functions of yRad6 and yBre1, respectively, in H2B ubiquitylation. However, there have been no corresponding biochemical analyses demonstrating intrinsic enzyme activities of yRad6 and yBre1 or related mechanistic details. Here, we describe a robust in vitro chromatin ubiquitylation assay that involves purified H2B ubiquitylation factors and natural nucleosomes. Our results indicate that yRad6 has an in vitro ability to nonspecifically ubiquitylate all core histones in the absence of an ubiquitin ligase but that yBre1 functions, through direct interactions with yRad6, to direct the ubiquitin conjugating activity of yRad6 toward the physiological H2B ubiquitylation site. Moreover, a yRad6 doma

SUBMITTER: Kim J 

PROVIDER: S-EPMC2742823 | biostudies-literature | 2009 Jul

REPOSITORIES: biostudies-literature