Net1 Stimulates RNA Polymerase I Transcription and Regulates Nucleolar Structure Independently of Controlling Mitotic Exit

• Published in: Molecular cell 2001-07, Vol.8 (1), p.45-55
• Main Authors: Shou, Wenying, Sakamoto, Kathleen M, Keener, John, Morimoto, Kenji W, Traverso, Edwin E, Azzam, Ramzi, Hoppe, Georg J, Feldman, R.M.Renny, DeModena, John, Moazed, Danesh, Charbonneau, Harry, Nomura, Masayasu, Deshaies, Raymond J
• Format: Article
• Language: English
• Subjects: Animals; Blotting, Northern; Cdc14 protein; Cell Cycle Proteins - genetics; Cell Cycle Proteins - metabolism; Cell Nucleolus - physiology; Cell Nucleolus - ultrastructure; Fungal Proteins - genetics; Fungal Proteins - metabolism; Histone Deacetylases - genetics; Histone Deacetylases - metabolism; In Situ Hybridization, Fluorescence; Microscopy, Fluorescence; Mitosis - physiology; Net1 protein; Nop1 protein; Nuclear Proteins - genetics; Nuclear Proteins - metabolism; Nucleic Acid Conformation; Phenotype; Pol1 Transcription Initiation Complex Proteins; Protein Tyrosine Phosphatases; Recombinant Fusion Proteins - genetics; Recombinant Fusion Proteins - metabolism; RENT complex; Ribonucleoproteins, Small Nucleolar; RNA Polymerase I - metabolism; RNA, Ribosomal - biosynthesis; RNA, Ribosomal - genetics; Saccharomyces cerevisiae; Saccharomyces cerevisiae - physiology; Saccharomyces cerevisiae Proteins; Silent Information Regulator Proteins, Saccharomyces cerevisiae; Sir2 protein; Sirtuin 2; Sirtuins; Spores, Fungal - physiology; Temperature; Trans-Activators - genetics; Trans-Activators - metabolism; Transcription Factors - genetics; Transcription Factors - metabolism; Transcription, Genetic
• ISSN: 1097-2765; 1097-4164
• DOI: 10.1016/S1097-2765(01)00291-X

The budding yeast RENT complex, consisting of at least three proteins (Net1, Cdc14, Sir2), is anchored to the nucleolus by Net1. RENT controls mitotic exit, nucleolar silencing, and nucleolar localization of Nop1. Here, we report two new functions of Net1. First, Net1 directly binds Pol I and stimulates rRNA synthesis both in vitro and in vivo. Second, Net1 modulates nucleolar structure by regulating rDNA morphology and proper localization of multiple nucleolar antigens, including Pol I. Importantly, we show that the nucleolar and previously described cell cycle functions of the RENT complex can be uncoupled by a dominant mutant allele of CDC14. The independent functions of Net1 link a key event in the cell cycle to nucleolar processes that are fundamental to cell growth.