RNA polymerase I stability couples cellular growth to metal availability.

ABSTRACT: Zinc is an essential cofactor of all major eukaryotic RNA polymerases. How the activity of these enzymes is coordinated or regulated according to cellular zinc levels is largely unknown. Here we show that the stability of RNA polymerase I (RNAPI) is tightly coupled to zinc availability in vivo. In zinc deficiency, RNAPI is specifically degraded by proteolysis in the vacuole in a pathway dependent on the export in Xpo1p and deubiquitination of the RNAPI large subunit Rpa190p by Ubp2p and Ubp4p. RNAPII is unaffected, which allows for the expression of genes required in zinc deficiency. RNAPI export to the vacuole is required for survival during zinc starvation, suggesting that degradation of zinc-binding subunits might provide a last resort zinc reservoir. These results reveal a hierarchy of

SUBMITTER: Lee YJ 

PROVIDER: S-EPMC3713077 | biostudies-literature | 2013 Jul

REPOSITORIES: biostudies-literature