Genome-wide transcriptional response to altered levels of the Rpb7 subunit of RNA polymerase II identifies its role in DNA damage response in Schizosaccharomyces pombe.

Abstract

Transcription of protein-coding genes is a highly regulated process. In eukaryotes, it involves cross-talk between the RNA polymerase II enzyme and different proteins of the transcriptional machinery. Twelve different subunits, Rpb1 to Rpb12, constitute RNA polymerase II. The sequence of the Rpb7 subunit is highly conserved across organisms. However, our knowledge and understanding of the role of Rpb7 in Schizosaccharomyces pombe is still limited. Therefore, in the present study we have studied the transcriptional response of S. pombe cells expressing reduced levels of rpb7+. Our global transcriptional analysis revealed that expression of genes belonging to different DNA repair pathways was downregulated by reduced rpb7+ expression. It was observed that survival of S. pombe cells expressing low rpb7+ levels was compromised under genotoxic stress conditions. Rpb7 also exhibited genetic interaction with genes of various DNA repair pathways. Furthermore, the growth sensitivity of S. pombe cells with low rpb7+ levels under DNA-damaging conditions was completely rescued by human Rpb7, indicating a functional conservation between these proteins. In summary, results from our whole-genome level gene expression analysis, as well as phenotypic and genetic experiments suggest a role for Rpb7 in DNA damage response in S. pombe.