The promoter-proximal rDNA terminator augments initiation by preventing disruption of the stable transcription complex caused by polymerase read-in.

S. L. Henderson, K. Ryan, B. Sollner-Webb

Research output: Contribution to journalArticle

Abstract

We have examined the mechanism by which transcriptional initiation at the mouse rDNA promoter is augmented by the RNA polymerase I terminator element that resides just upstream of it. Using templates in which terminator elements are instead positioned at the opposite side of the plasmid rather than proximal to the promoter, or conditions where transcription is terminated elsewhere in the plasmid by UV-induced lesions, we show that the terminator's stimulatory effect is not position dependent. Mouse terminator elements therefore do not stimulate via the previously postulated 'read-through enhancement' model in which terminated polymerases are handed off to an adjacent promoter in a concerted reaction. The position independence and orientation dependence of the terminator also makes it unlikely that the terminator functions as a promoter element or as an enhancer. Instead, terminators serve to augment initiation by preventing polymerases from reading completely around the plasmid and through the promoter from upstream, an event which we show interferes with subsequent rounds of initiation. Notably, this transcriptional interference arises because polymerase passage across a promoter disrupts the otherwise stable transcription complex, specifically releasing the bound transcription factor D. These liberated D molecules can then bind to other templates and activate their expression. The rDNA transcriptional interference is not due to a steric impediment to the binding of new polymerase molecules, and it does not similarly liberate the initiation-competent polymerase (factor C). These studies have also convincingly demonstrated that multiple rounds of transcription are obtained from rDNA template molecules in vitro.

Original languageEnglish (US)
Pages (from-to)212-223
Number of pages12
JournalGenes & development
Volume3
Issue number2
DOIs
StatePublished - Feb 1989

ASJC Scopus subject areas

  • Genetics
  • Developmental Biology

Fingerprint Dive into the research topics of 'The promoter-proximal rDNA terminator augments initiation by preventing disruption of the stable transcription complex caused by polymerase read-in.'. Together they form a unique fingerprint.

  • Cite this