R-loop formation during S phase is restricted by PrimPol-mediated repriming

Šviković, Sasa, Crisp, Alastair, Tan-Wong, Sue Mei, Guilliam, Thomas Alex, Doherty, Aidan, Proudfoot, Nicholas, Guilbaud, Guillaume and Sale, Julian (2018) R-loop formation during S phase is restricted by PrimPol-mediated repriming. The EMBO Journal. ISSN 0261-4189

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During DNA replication conflicts with ongoing transcription are frequent and require careful management to avoid genetic instability. R-loops, three stranded nucleic acid structures comprising a DNA:RNA hybrid and displaced single stranded DNA, are important drivers of damage arising from such conflicts. How R-loops stall replication and the mechanisms that restrain their formation during S phase are incompletely understood. Here we show in vivo how R-loop formation drives a short purine-rich repeat, (GAA)10, to become a replication impediment that engages the repriming activity of the primase-polymerase PrimPol. Further, the absence of PrimPol leads to significantly increased R-loop formation around this repeat during S phase. We extend this observation by showing that PrimPol suppresses R-loop formation in genes harbouring secondary structure-forming sequences, exemplified by G quadruplex and H-DNA motifs, across the genome in both avian and human cells. Thus, R- loops promote the creation of replication blocks at susceptible structure-forming sequences, while PrimPol-dependent repriming limits the extent of unscheduled R-loop formation at these sequences, mitigating their impact on replication.

Item Type: Article
Keywords: DNA secondary structures / PrimPol / replication / repriming / R-loops
Schools and Departments: School of Life Sciences > Sussex Centre for Genome Damage and Stability
Research Centres and Groups: Genome Damage and Stability Centre
Depositing User: Aidan Doherty
Date Deposited: 09 Jan 2019 16:10
Last Modified: 09 Jan 2019 16:11
URI: http://srodev.sussex.ac.uk/id/eprint/81207

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Project NameSussex Project NumberFunderFunder Ref
The role of a novel family of eukaryotic DNA polymerases in mitochondrial DNA replicationG0207BBSRC-BIOTECHNOLOGY & BIOLOGICAL SCIENCES RESEARCH COUNCILBB/H019723/1
Understanding the role of PrimPol in damage tolerance during genome replication in eukaryotic cellsG1621BBSRC-BIOTECHNOLOGY & BIOLOGICAL SCIENCES RESEARCH COUNCILBB/M008800/1