Chromatin-associated factor that regulates transcription (By similarity). Regulates Pol I-mediated rRNA biogenesis and, probably, Pol III-mediated transcription (By similarity). Regulates the epigenetic status of rDNA (By similarity). Associates with the RNA polymerase (Pol I) complex. Interacts with POLR1E. Associates with chromatin regions of rDNA. Belongs to the WD repeat PWP1 family.