Rrp14 controls rRNA transcription via facilitating the translocation of Pol5 into the nucleolus

Rrp14 is a conserved protein that plays an important role in rRNA processing and ribosomal biogenesis. In <i>Schizosaccharomyces pombe</i>, the <i>rrp14</i> gene is split into <i>SPAC8C9.10 c</i> (<i>rrp14</i>) and <i>SPBC947.07</i> (<i>rrp1402</i>). Although the <i>SPAC8C9.10 c</i> gene is not essential for <i>S. pombe</i> survival, deletion of the gene causes the yeast cells to grow sick and to exhibit decreased rRNA transcription. We identified a novel Pol5 protein that physically interacts with the Rrp14 protein. Taking advantage of the Pil1 co-tethering assay, we found that Rrp14 facilitates the nucleolus translocation of Pol5, and the 7-RINAWN-12 motif of the Rrp14 protein is responsible for the interaction between Pol5 and Rrp14. Since deletion of the 7-RINAWN-12 motif affects rRNA transcription, we thus propose that Rrp14 affects rRNA transcription by facilitating the nucleolus translocation of Pol5.