Co-transcriptional RNA cleavage provides a failsafe termination mechanism for yeast RNA polymerase I.

Journal article

Ribosomal RNA, transcribed by RNA polymerase (Pol) I, accounts for most cellular RNA. Since Pol I transcribes rDNA repeats with high processivity and polymerase density, transcription termination is a critical process. Early in vitro studies proposed polymerase pausing by Reb1 and transcript release at the T-rich element T1 determined transcription termination. However recent in vivo studies revealed a 'torpedo' mechanism for Pol I termination: co-transcriptional RNA cleavage by Rnt1 provides an entry site for the 5'-3' exonuclease Rat1 that degrades Pol I-associated transcripts destabilizing the transcription complex. Significantly Rnt1 inactivation in vivo reveals a second co-transcriptional RNA cleavage event at T1 which provides Pol I with an alternative termination pathway. An intact Reb1-binding site is also required for Rnt1-independent termination. Consequently our results reconcile the original Reb1-mediated termination pathway as part of a failsafe mechanism for this essential transcription process.

Authors: Braglia, P; Kawauchi, J; Proudfoot, N

• Publication status: Published
• Peer review status: Peer reviewed
• Publisher: Oxford University Press
• Journal: Nucleic acids research
• Volume: 39
• Issue: 4
• Pages: 1439-1448
• Publication date: 2011-03-01
• DOI: 10.1093/nar/gkq894
• EISSN: 1362-4962
• ISSN: 0305-1048
• Language: English
• Keywords: RNA, Ribosomal; DNA, Ribosomal; Ribonuclease III; Mutagenesis; RNA Helicases; RNA Polymerase I; Saccharomyces cerevisiae; Transcription Factors; DNA-Binding Proteins; Saccharomyces cerevisiae Proteins; Thymine; Gene Deletion; Transcription, Genetic; Terminator Regions, Genetic; Exoribonucleases; DNA Helicases