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R-loop formation during S phase is restricted by PrimPol-mediated repriming.
Saša Šviković1, Alastair Crisp1, Sue Mei Tan-Wong2
1MRC Laboratory of Molecular Biology, Cambridge, UK.
The EMBO Journal
|November 28, 2018
Summary
Replication-transcription conflicts create R-loops, which stall DNA replication. The PrimPol enzyme suppresses R-loop formation at repetitive DNA sequences, preventing replication blocks and maintaining genetic stability.
Area of Science:
- Molecular Biology
- Genetics
- Genomics
Background:
- DNA replication and transcription frequently conflict, potentially causing genetic instability.
- R-loops, DNA:RNA hybrids, are key structures driving damage from these conflicts.
- Mechanisms restraining R-loop formation during S phase are not fully understood.
Purpose of the Study:
- To investigate how R-loop formation impedes DNA replication.
- To elucidate the role of PrimPol in managing R-loops during S phase.
- To determine how PrimPol suppresses R-loop formation at specific DNA sequences.
Main Methods:
- In vivo studies using avian and human cells.
- Analysis of R-loop formation around (GAA)10 repeats.
- Investigating the interaction between R-loops and the PrimPol enzyme.
- Genome-wide assessment of R-loop formation at secondary structure motifs.
Main Results:
- R-loop formation at (GAA)10 repeats creates a replication impediment.
- PrimPol's repriming activity is engaged by these R-loop-induced impediments.
- Absence of PrimPol significantly increases R-loop formation at these repeats during S phase.
- PrimPol suppresses R-loop formation at G quadruplex and H-DNA motifs genome-wide.
Conclusions:
- R-loops cause replication blocks at structure-forming DNA sequences.
- PrimPol-dependent repriming limits unscheduled R-loop formation.
- PrimPol mitigates the impact of R-loops on replication, ensuring genetic stability.
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