Novel transcriptional regulation by pruning RNA polymerase II during transcription elongation
The external regulation of the elongation response of eukaryotic transcription is not fully understood. To address this question, we have shown that in budding yeast, Esc2 and Rad57, which are involved in homologous recombination repair of double-stranded DNA breaks, cooperate with Sit4, a PP2A-type protein phosphatase, and its partner Rrd1, a peptidylprolyl isomerase (PPIase), to repress transcription of specific genes by removing RNA polymerase II during elongation. This RNA polymerase removal system not only prevents specific gene clusters, such as the house-keeping genes, from overaccumulating transcription elongation factors, but also distributes them to transiently expressed genes, such as cell cycle regulatory gene clusters.