5′-end surveillance by Xrn2 acts as a shared mechanism for mammalian pre-rRNA maturation and decay

Minshi Wang, Dimitri G. Pestov

Research output: Contribution to journalArticlepeer-review

53 Scopus citations

Abstract

Ribosome biogenesis requires multiple nuclease activities to process pre-rRNA transcripts into mature rRNA species and eliminate defective products of transcription and processing. We find that in mammalian cells, the 5′ exonuclease Xrn2 plays a major role in both maturation of rRNA and degradation of a variety of discarded pre-rRNA species. Precursors of 5.8S and 28S rRNAs containing 5′ extensions accumulate in mouse cells after siRNA-mediated knockdown of Xrn2, indicating similarity in the 5′-end maturation mechanisms between mammals and yeast. Strikingly, degradation of many aberrant pre-rRNA species, attributed mainly to 3′ exonucleases in yeast studies, occurs 5′ to 3′ in mammalian cells and is mediated by Xrn2. Furthermore, depletion of Xrn2 reveals pre-rRNAs derived by cleavage events that deviate from the main processing pathway. We propose that probing of pre-rRNA maturation intermediates by exonucleases serves the dual function of generating mature rRNAs and suppressing suboptimal processing paths during ribosome assembly.

Original languageEnglish (US)
Pages (from-to)1811-1822
Number of pages12
JournalNucleic acids research
Volume39
Issue number5
DOIs
StatePublished - Mar 2011

All Science Journal Classification (ASJC) codes

  • Genetics

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