Impairment of transcription elongation by R-loops in vitro

Biochem Biophys Res Commun. 2007 Aug 24;360(2):428-32. doi: 10.1016/j.bbrc.2007.06.098. Epub 2007 Jun 25.


Transcription elongation causes a local change in DNA superhelicity. An excess of negative supercoiling may lead to opening of DNA strands that could allow formation of R-loops. In yeast, mutants of the THO complex are impaired in transcription elongation and this defect has been linked to co-transcriptional formation of R-loops, which could constitute roadblocks for RNA polymerases. In this study, we found that stably formed 300-nt long DNA-RNA hybrids in a negatively supercoiled transcription template reduced the efficiency of transcription elongation by half, providing a first experimental evidence that transcription elongation is impaired by R-loops in vitro.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • DNA Damage / genetics*
  • DNA, Fungal / chemistry*
  • DNA, Fungal / genetics*
  • RNA, Fungal / chemistry*
  • RNA, Fungal / genetics*
  • Structure-Activity Relationship
  • Transcription, Genetic / genetics*
  • Transcriptional Elongation Factors / chemistry
  • Transcriptional Elongation Factors / genetics*


  • DNA, Fungal
  • RNA, Fungal
  • Transcriptional Elongation Factors