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Disease-associated DNA2 nuclease-helicase protects cells from lethal chromosome under-replication
Benoît Falquet1,2, Gizem Ölmezer1,2, Franz Enkner1
1Friedrich Miescher Institute for Biomedical Research, CH-4058 Basel, Switzerland.
Nucleic Acids Research
|June 17, 2020
Summary
DNA2 is crucial for DNA replication fork recovery. Its absence causes chromosome under-replication, exacerbated by PIF1, highlighting DNA2
Area of Science:
- Molecular Biology
- Genetics
- Cell Biology
Background:
- DNA2 is an essential nuclease-helicase involved in DNA repair and replication.
- Its absence leads to inviability, which can be rescued by deleting PIF1 or RAD9.
- Pif1 is proposed to promote 5'-flap accumulation during Okazaki fragment maturation, with Dna2 removing these intermediates.
Purpose of the Study:
- To investigate the essential function of DNA2 in replication fork (RF) recovery.
- To elucidate the interplay between Dna2, Pif1, and the DNA damage checkpoint in maintaining genome stability.
- To understand the role of DNA2 in chromosome replication and its implications for diseases like Seckel syndrome and cancer.
Main Methods:
- Utilized Saccharomyces cerevisiae as a model organism.
- Investigated the effects of dna2Δ mutations, alone and in combination with pif1Δ and rad9Δ.
- Analyzed chromosome under-replication and DNA damage checkpoint activation in response to RF stalling.
Main Results:
- Loss of Dna2 leads to severe chromosome under-replication downstream of stalled RFs.
- Pif1 exacerbates unfaithful chromosome replication in Dna2-mutant cells by triggering the DNA damage checkpoint.
- Pif1 promotes homologous recombination-coupled replication, contributing to checkpoint activation.
Conclusions:
- DNA2 is essential for promoting RF recovery and replication completion.
- DNA2 suppresses excessive recombination-dependent replication (RDR) and checkpoint activation at stalled RFs.
- DNA2's role in controlling stalled RF fate provides a rationale for its involvement in Seckel syndrome and cancer.
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