Chromatin-associated factor that regulates transcription (PubMed:21752937). Regulates Pol I-mediated rRNA biogenesis and, probably, Pol III-mediated transcription (PubMed:29065309). Regulates the localization to the nucleolus of Cdk7, a regulator of the Pol I-elongation factor TFIIH (PubMed:29065309). Acts as regulator of cell proliferation and tissue growth as part of the TORC1 and Myc signaling pathway in response to nutrients (PubMed:29065309). Required in males for both germline stem cell (GSC) maintenance and early stages of germ cell differentiation of germ cell cysts (PubMed:21752937). Not required for female germline stem cell (GSC) maintenance, but necessary to regulate germ cell differentiation and egg chamber development (PubMed:21752937). In female somatic cells, required for follicle stem cell survival and maintenance (PubMed:21752937). Interacts with Mybbp1A. Co-localizes with active forms of RNA polymerase II (PubMed:21752937). Associates with open chromatin and chromosomal puffs of polytene chromosomes in larval salivary glands (PubMed:21752937). Nucleolar localization is controlled by mTORC1 signaling (PubMed:29065309). Detected in the germline of adult testis and ovary (at protein level) (PubMed:21752937). Detected in ovary somatic cells, in zfh1-positive cyst cells in the testis and absent in differentiated cyst cells (at protein level) (PubMed:21752937). Detected in embryonic cell types, including germ cells (at protein level) (PubMed:21752937). In early third instar larvae, detected in the fat body (at protein level) (PubMed:29065309). Detected in the larval salivary glands and fat body (at protein level) (PubMed:21752937). Expressed in stage 17 embryos in male but not female gonads (PubMed:21752937). Increased expression upon activation of the Insulin/TOR/Myc pathway in response to protein diet. Phosphorylated in response to nutrient-activated TORC1 signaling. Larval mutants exhibit altered cell transcription with reduced levels of Pol I-dependent rRNA biogenesis and, to a certain extent, of III-dependent transcription leading to reduced growth (PubMed:21752937, PubMed:29065309). Displays delayed pupation kinetics and reduced pupal volume (PubMed:29065309). Exhibits reduced number of germline cells leading to fertility defects; female flies have limited fertility, whereas male flies are sterile (PubMed:21752937). In male larvae, germ cells can enter differentiation but spermatogenic cysts cannot develop normally (PubMed:21752937). Adult testes shows fewer hub-proximal germ cells, lack of Stat92e activation and general failure of germline stem cells (GSC) maintenance (PubMed:21752937). RNAi-mediated knockdown in the posterior compartment of the developing wing leads to reduced compartment size (PubMed:29065309). RNAi-mediated knockdown in the fat body results in delayed larval development and reduced pupal volume (PubMed:29065309). Belongs to the WD repeat PWP1 family. Extended N-terminus.