Active destruction of defective ribosomes by a ubiquitin ligase involved in DNA repair.

Progression of DNA replication forks through damaged DNA requires a ubiquitin ligase comprised of the cullin Rtt101, the RING finger protein Hrt1, and the adaptor protein Mms1. Rtt101 and Mms1 were implicated recently by Fujii and colleagues (pp. 963-974) in the degradation of catalytically inactive mutant 25S ribosomal RNAS (rRNAs) in mature 60S ribosomal subunits, a process that requires ubiquitin and is accompanied by ubiquitination of 60S components. It now seems likely that the same ubiquitin ligase is enlisted to deal with defective rRNA and damaged DNA.