ESA1 IS A HISTONE ACETYLTRANSFERASE THAT IS ESSENTIAL FOR GROWTH IN YEAST

Posttranslational acetylation of core histone amino termini has long b een associated with transcriptionally active chromatin. Recent reports have demonstrated histone acetyltransferase activity in a small group of conserved transcriptional regulators directly linked to gene activ ation. In addition, the presence of a putative acetyltransferase domai n has been discovered in a group of proteins known as the MYST family (for its founding members MOZ, YBF2/SAS3, SAS2, and Tip60). Members of this family are implicated in acute myeloid leukemia (MOZ), transcrip tional silencing in yeast (SAS2 and YBF2/SAS3), HIV Tat interaction in humans (Tip60), and dosage compensation in Drosophila (MOF). In this report, we express a yeast ORF with homology to MYST family members an d show it possesses histone acetyltransferase activity. Unlike the oth er MYST family members in Saccharomyces cerevisiae this gene is essent ial for growth.