Sir2 suppresses transcription-mediated displacement of Mcm2-7 replicative helicases at the ribosomal DNA repeats.

Journal Article (Journal Article)

Repetitive DNA sequences within eukaryotic heterochromatin are poorly transcribed and replicate late in S-phase. In Saccharomyces cerevisiae, the histone deacetylase Sir2 is required for both transcriptional silencing and late replication at the repetitive ribosomal DNA arrays (rDNA). Despite the widespread association between transcription and replication timing, it remains unclear how transcription might impinge on replication, or vice versa. Here we show that, when silencing of an RNA polymerase II (RNA Pol II)-transcribed non-coding RNA at the rDNA is disrupted by SIR2 deletion, RNA polymerase pushes and thereby relocalizes replicative Mcm2-7 helicases away from their loading sites to an adjacent region with low nucleosome occupancy, and this relocalization is associated with increased rDNA origin efficiency. Our results suggest a model in which two of the major defining features of heterochromatin, transcriptional silencing and late replication, are mechanistically linked through suppression of polymerase-mediated displacement of replication initiation complexes.

Full Text

Duke Authors

Cited Authors

  • Foss, EJ; Gatbonton-Schwager, T; Thiesen, AH; Taylor, E; Soriano, R; Lao, U; MacAlpine, DM; Bedalov, A

Published Date

  • May 2019

Published In

Volume / Issue

  • 15 / 5

Start / End Page

  • e1008138 -

PubMed ID

  • 31083663

Pubmed Central ID

  • PMC6532929

Electronic International Standard Serial Number (EISSN)

  • 1553-7404

Digital Object Identifier (DOI)

  • 10.1371/journal.pgen.1008138


  • eng

Conference Location

  • United States