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Updated: Jun 3, 2026
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Detection of Post-Replicative Gaps Accumulation and Repair in Human Cells Using the DNA Fiber Assay
Published on: February 3, 2022
Human HEL308 localizes to damaged replication forks and unwinds lagging strand structures
Agnieszka A Tafel1, Leonard Wu, Peter J McHugh
1Weatherall Institute of Molecular Medicine, University of Oxford, John Radcliffe Hospital, Oxford, UK.
The Journal of Biological Chemistry
|March 15, 2011
Summary
Human HEL308 (Hlj1) protein unwinds DNA at stalled replication forks, aiding repair. It targets single-stranded DNA junctions, facilitating replication restart by opening parental strands for repair factors.
Area of Science:
- Molecular Biology
- DNA Repair Mechanisms
- Biochemistry
Background:
- HEL308 is a conserved DNA helicase family involved in DNA repair.
- Human HEL308 (Hlj1) is an ATP-dependent enzyme unwinding DNA with 3' to 5' polarity.
- Its precise mechanism and role in replication fork repair remain largely unknown.
Purpose of the Study:
- To elucidate the mechanism and function of human HEL308 at stalled replication forks.
- To investigate HEL308's localization, substrate specificity, and interactions with other repair proteins.
Main Methods:
- Utilized GFP-tagged HEL308 for cellular localization studies post-camptothecin treatment.
- Performed biochemical assays with purified HEL308 on model DNA substrates.
- Investigated HEL308's interaction and stimulation by replication protein A (RPA).
Main Results:
- GFP-HEL308 localizes to replication forks and colocalizes with Rad51 and FANCD2.
- Purified HEL308 requires a 3' single-stranded DNA region for loading and unwinding.
- HEL308 preferentially unwinds parental strands at stalled fork models and is stimulated by RPA.
- HEL308 targets the junction between single-stranded and double-stranded DNA.
Conclusions:
- HEL308 plays a role in repairing stalled replication forks by unwinding parental DNA strands.
- This unwinding action likely facilitates the recruitment of homologous recombination factors for replication restart.
- HEL308 functions at the interface of single-stranded and double-stranded DNA at damaged fork sites.
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