A role for ubiquitin in the clearance of nonfunctional rRNAs
- 1Institute for Virus Research, Kyoto University, Kyoto 606-8507, Japan;
- 2PRESTO, Japan Science and Technology Agency, Tokyo 102-0075, Japan;
- 3CREST, Japan Science and Technology Agency, Tokyo 102-0075, Japan
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↵4 These authors contributed equally to this work.
Abstract
Quality control mechanisms operate in various steps of ribosomal biogenesis to ensure the production of functional ribosome particles. It was reported previously that mature ribosome particles containing nonfunctional mutant rRNAs are also recognized and selectively removed by a cellular quality control system (nonfunctional rRNA decay [NRD]). Here, we show that the NRD of 25S rRNA requires a ubiquitin E3 ligase component Rtt101p and its associated protein Mms1p, identified previously as factors involved in DNA repair. We revealed that a group of proteins associated with nonfunctional ribosome particles are ubiquitinated in a Rtt101–Mms1-dependent manner. 25S NRD was disrupted when ubiquitination was inhibited by the overexpression of modified ubiquitin molecules, demonstrating a direct role for ubiquitin in this pathway. These results uncovered an unexpected connection between DNA repair and the quality control of rRNAs. Our findings support a model in which responses to DNA and rRNA damages are triggered by a common ubiquitin ligase complex during genotoxic stress harmful to both molecules.
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Footnotes
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↵5 Corresponding authors.
↵E-MAIL kmakoto{at}virus.kyoto-u.ac.jp; FAX 81-75-751-3992.
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↵6 E-MAIL hitoohno{at}virus.kyoto-u.ac.jp; FAX 81-75-751-3992.
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Article is online at http://www.genesdev.org/cgi/doi/10.1101/gad.1775609.
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Supplemental material is available at http://www.genesdev.org.
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- Received December 23, 2008.
- Accepted March 12, 2009.
- Copyright © 2009 by Cold Spring Harbor Laboratory Press