Role of Histone Ubiquitylation and Deubiquitylation as Determined by the Analysis of an HTB1_K123R S. cerevisiae Strain

ABSTRACT: In Saccharomyces cerevisiae histone H2B is ubiquitylated at lysine 123. The SAGA complex component, Ubp8, is one of two proteases that remove this ubiquitin moiety. We analyzed gene expression in a strain containing a variant of histone H2B with lysine 123 converted to arginine to address the mechanisms by which ubiquitylation and deubiquitylation of histone H2B affects gene expression. We show that changes in gene expression observed upon deletion of ubp8 are suppressed by htb1K123R. This provides genetic evidence that Ubp8 alters gene expression through deubiquitylation of histone H2B. Second, microarray analyses of the htb1K123R strain show that loss of histone ubiquitylation results in a two-fold or greater change in expression of ~1.5% of the protein coding genes with greater than two-thirds increasing. For genes in which ubiquitylation represses expression, ubiquitylation principally acts through its effects on histone methylation. In contrast, decreased expression of the CWP1 gene was not paralleled by deletions of the methyltransferase components Swd3, Set2 or Dot1 and is thus likely independent of methylation. Finally, by comparing gene expression changes in the htb1K123R strain with those in a strain deleted for rad6, we conclude that lysine 123 affects transcription primarily because of its being a site of ubiquitylation. Keywords: yeast, histone ubiquitylation, Ubp8, gene expression, genetic modification, histone H2B Two dye-swapped, biological replicate experiments were performed for yeast strains CY1272(Htb1_K123R;htb2_delta0), BY10809(ubp8_delta0) and CY1383(Htb1_K123R;htb2_delta0;ubp8_delta0) with reference to BY4742(wt). Three biological replicates, including one dye-swap experiment, were performed comparing CY1272(Htb1_K123R;htb2_delta0) to BY13026(htb2_delta0).

ORGANISM(S): Saccharomyces cerevisiae

SUBMITTER: Gaoyang Liang 

PROVIDER: E-GEOD-6316 | biostudies-arrayexpress |

REPOSITORIES: biostudies-arrayexpress