Budding yeast RNA polymerases I and II employ parallel mechanisms of transcriptional termination
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↵1 These authors contributed equally to this work.
Abstract
Both RNA polymerase I and II (Pol I and Pol II) in budding yeast employ a functionally homologous “torpedo-like” mechanism to promote transcriptional termination. For two well-defined Pol II-transcribed genes, CYC1 and PMA1, we demonstrate that both Rat1p exonuclease and Sen1p helicase are required for efficient termination by promoting degradation of the nascent transcript associated with Pol II, following mRNA 3′ end processing. Similarly, Pol I termination relies on prior Rnt1p cleavage at the 3′ end of the pre-rRNA 35S transcript. This is followed by the combined actions of Rat1p and Sen1p to degrade the Pol I-associated nascent transcript that consequently promote termination in the downstream rDNA spacer sequence. Our data suggest that the previously defined in vitro Pol I termination mechanism involving the action of the Reb1p DNA-binding factor to “road-block” Pol I transcription close to the termination region may have overlooked more complex in vivo molecular processes.
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Footnotes
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↵2 Corresponding author.
↵2 E-MAIL Nicholas.proudfoot{at}path.ox.ac.uk; FAX 44-1865-275556.
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Supplemental material is available at http://www.genesdev.org.
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Article is online at http://www.genesdev.org/cgi/doi/10.1101/gad.463408.
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- Received November 13, 2007.
- Accepted February 29, 2008.
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Freely available online through the Genes & Development Open Access option.
- Copyright © 2008, Cold Spring Harbor Laboratory Press