Ume6p represses early meiotic gene transcription in Saccharomyces cerevisiae by 
recruiting the Rpd3p histone deacetylase and chromatin-remodeling proteins. 
Ume6p repression is relieved in a two-step destruction process mediated by the 
anaphase-promoting complex/cyclosome (APC/C) ubiquitin ligase. The first step 
induces partial Ume6p degradation when vegetative cells shift from glucose- to 
acetate-based medium. Complete proteolysis happens only upon meiotic entry. Here 
we demonstrate that the first step in Ume6p destruction is controlled by its 
acetylation and deacetylation by the Gcn5p acetyltransferase and Rpd3p, 
respectively. Ume6p acetylation occurs in medium lacking dextrose and results in 
a partial destruction of the repressor. Preventing acetylation delays Ume6p 
meiotic destruction and retards both the transient transcription program and 
execution of the meiotic nuclear divisions. Conversely, mimicking acetylation 
induces partial destruction of Ume6p in dextrose medium and accelerates meiotic 
degradation by the APC/C. These studies reveal a new mechanism by which 
acetyltransferase activity induces gene expression through targeted destruction 
of a transcriptional repressor. These findings also demonstrate an important 
role for nonhistone acetylation in the transition between mitotic and meiotic 
cell division.