Generation and characterization of a temperature-sensitive mutant allele of the second largest subunit of RNA polymerase I in Schizosaccharomyces pombe

RNA polymerase I (Pol I) is a highly conserved complex that catalyzes the transcription of rRNA precursors in the nucleolus. In this study, we isolated a temperature-sensitive (ts) allele of Rpa2, the second largest subunit of Pol I in the fission yeast Schizosaccharomyces pombe . We found that rpa2 (ts) cells were severely defective in growth at temperatures above 32 °C. We also found that rpa2 (ts) cells showed aberrant chromosome segregation and an abnormal ring-like nuclear structure at the restrictive temperature. These findings suggest that Rpa2 is essential for faithful nuclear division and nuclear structural organization in S. pombe .