A novel histone acetyltransferase is an integral subunit of elongating RNApolymerase II holoenzyme

The elongator complex is a major component of the RNA polymerase II (RNAPII ) holoenzyme responsible for transcriptional elongation in yeast. Here we i dentify Elp3, the 60-kilodalton subunit of elongator/RNAPII holoenzyme, as a highly conserved histone acetyltransferase (HAT) capable of acetylating c ore histones in vitro. In vivo, ELP3 gene deletion confers typical elp phen otypes such as slow growth adaptation, slow gene activation, and temperatur e sensitivity. These results suggest a role for a novel, tightly RNAPII-ass ociated HAT in transcription of DNA packaged in chromatin.