Modulating the level of the Rpb7 subunit of RNA polymerase II affects cell separation in Schizosaccharomyces pombe.

The rpb7(+) gene encodes the seventh largest subunit of RNA polymerase II and is essential for survival of yeast cells. To gain insight into its functions, we expressed rpb7(+) under the control of the nmt1 promoter and investigated its role in regulating multiple phenotypes in Schizosaccharomyces pombe. We observed that low rpb7(+) levels resulted in slow growth of cells under optimum growth conditions. However, no growth defect was observed under different stress conditions tested in this study. Our results also showed that the most prominent phenotype of cells expressing reduced rpb7(+) is a defect in cell separation. Quantitative real-time PCR analysis further revealed that the transcription of specific cell septation genes was significantly reduced in these cells. Collectively, results presented in this study highlight the distinct role of Rpb7p in regulating cell separation in S. pombe.