Net1 stimulates RNA polymerase I transcription and regulates nucleolar structure independently of controlling mitotic exit

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 re port two new functions of Net1. First, Net1 directly binds Pot I and stimul ates rRNA synthesis both in vitro and in vivo. Second, Net1 modulates nucle olar structure by regulating rDNA morphology and proper localization of mul tiple nucleolar antigens, including Pol l. Importantly, we show that the nu cleolar and previously described cell cycle functions of the RENT complex c an be uncoupled by a dominant mutant allele of CDC14. The independent funct ions of Net1 link a key event in the cell cycle to nucleolar processes that are fundamental to cell growth.