Affiliation:
1. Department of Biochemistry, University of Western Ontario, London, Canada N6A 5C1
Abstract
ABSTRACT
Transcription of the
Saccharomyces cerevisiae ARG1
gene is under the control of both positive and negative elements. Activation of the gene in minimal medium is induced by Gcn4. Repression occurs in the presence of arginine and requires the ArgR/Mcm1 complex that binds to two upstream arginine control (ARC) elements. With the recent finding that the E2 ubiquitin conjugase Rad6 modifies histone H2B, we examined the role of Rad6 in the regulation of
ARG1
transcription. We find that Rad6 is required for repression of
ARG1
in rich medium, with expression increased ∼10-fold in a
rad6
null background. Chromatin immunoprecipitation analysis indicates increased binding of TATA-binding protein in the absence of Rad6. The active-site cysteine of Rad6 is required for repression, implicating ubiquitination in the process. The effects of Rad6 at
ARG1
involve two components. In one of these, histone H2B is the likely target for ubiquitination by Rad6, since a strain expressing histone H2B with the principal ubiquitination site converted from lysine to arginine shows a fivefold relief of repression. The second component requires Ubr1 and thus likely the pathway of N-end rule degradation. Through the analysis of promoter constructs with ARC deleted and an
arg80 rad6
double mutant, we show that Rad6 repression is mediated through the ArgR/Mcm1 complex. In addition, analysis of an
ada2 rad6
deletion strain indicated that the SAGA acetyltransferase complex and Rad6 act in the same pathway to repress
ARG1
in rich medium.
Publisher
American Society for Microbiology
Subject
Cell Biology,Molecular Biology
Cited by
42 articles.
订阅此论文施引文献
订阅此论文施引文献,注册后可以免费订阅5篇论文的施引文献,订阅后可以查看论文全部施引文献