Managing Single-Stranded DNA during Replication Stress in Fission Yeast
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Department of Chemistry and Biology, Ryerson University, 350 Victoria Street Toronto, ON M5B 2K3, Canada
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Program in Molecular and Computational Biology, University of Southern California, 1050 Childs Way, Los Angeles, CA 90089, USA
*
Author to whom correspondence should be addressed.
Academic Editors: Fumio Hanaoka, Wolf-Dietrich Heyer and Thomas Helleday
Biomolecules 2015, 5(3), 2123-2139; https://doi.org/10.3390/biom5032123
Received: 31 July 2015
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Revised: 28 August 2015
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Accepted: 1 September 2015
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Published: 18 September 2015
(This article belongs to the Special Issue DNA Damage Response)
Replication fork stalling generates a variety of responses, most of which cause an increase in single-stranded DNA. ssDNA is a primary signal of replication distress that activates cellular checkpoints. It is also a potential source of genome instability and a substrate for mutation and recombination. Therefore, managing ssDNA levels is crucial to chromosome integrity. Limited ssDNA accumulation occurs in wild-type cells under stress. In contrast, cells lacking the replication checkpoint cannot arrest forks properly and accumulate large amounts of ssDNA. This likely occurs when the replication fork polymerase and helicase units are uncoupled. Some cells with mutations in the replication helicase (mcm-ts) mimic checkpoint-deficient cells, and accumulate extensive areas of ssDNA to trigger the G2-checkpoint. Another category of helicase mutant (mcm4-degron) causes fork stalling in early S-phase due to immediate loss of helicase function. Intriguingly, cells realize that ssDNA is present, but fail to detect that they accumulate ssDNA, and continue to divide. Thus, the cellular response to replication stalling depends on checkpoint activity and the time that replication stress occurs in S-phase. In this review we describe the signs, signals, and symptoms of replication arrest from an ssDNA perspective. We explore the possible mechanisms for these effects. We also advise the need for caution when detecting and interpreting data related to the accumulation of ssDNA.
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Keywords:
DNA replication; single-stranded DNA; replication stress; genome stability; RPA; Schizosaccharomyces pombe; checkpoint; MCM; helicase
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This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited
MDPI and ACS Style
Sabatinos, S.A.; Forsburg, S.L. Managing Single-Stranded DNA during Replication Stress in Fission Yeast. Biomolecules 2015, 5, 2123-2139. https://doi.org/10.3390/biom5032123
AMA Style
Sabatinos SA, Forsburg SL. Managing Single-Stranded DNA during Replication Stress in Fission Yeast. Biomolecules. 2015; 5(3):2123-2139. https://doi.org/10.3390/biom5032123
Chicago/Turabian StyleSabatinos, Sarah A., and Susan L. Forsburg. 2015. "Managing Single-Stranded DNA during Replication Stress in Fission Yeast" Biomolecules 5, no. 3: 2123-2139. https://doi.org/10.3390/biom5032123
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