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Updated: Jul 14, 2026

Artificial RNA Polymerase II Elongation Complexes for Dissecting Co-transcriptional RNA Processing Events
Published on: May 13, 2019
Impairment of transcription elongation by R-loops in vitro
Cristina Tous1, Andrés Aguilera
1Departamento de Genética, Facultad de Biología, and Departamento de Biología Molecular, CABIMER, CSIC-Universidad de Sevilla, Av. Américo Vespucio s/n, 41092 Sevilla, Spain.
Abstract:
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.
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