The histone methylase Set2p and the histone deacetylase Rpd3p repress meiotic recombination at the HIS4 meiotic recombination hotspot in Saccharomyces cerevisiae

The rate of meiotic recombination in the yeast Soccharomyces cerevisiae varies widely in different regions of the genome with some genes having very high levels of recombination (hotspots). Avariety of experiments donein yeast suggest thathotspots are a feature of chromatin structure rather than a feature of primary DNA sequence. We examined the effects of mutating a variety of enzymes that affect chromatin structure on the recombination activity of the well -characterized HIS4 hotspot including the Set2p and Dotlp histone methylases, the Hdalp and Rpd3p histone deacetylases, the Sin4p global transcription regulator, and a deletion of one of the two copies of the genes encoding histone H3-H4. Loss of Set2p or Rpd3p substantially elevated HIS4 hotspot activity, and loss of Hdalp had a smaller stimulatory effect; none of the other alterations had a significant effect. The increase of HIS4 hotspot activity in set2 and rpd3 strains is likely to be related to the recent finding that histone H3 methylation by Set2p directs deacetylation of histones by Rpd3p. (c) 2008 Elsevier B.V All rights reserved.