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Genome instability induced by structured DNA and replication fork restart

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posted on 2023-06-08, 11:26 authored by Stephanie Schalbetter
DNA replication is a central mechanism to all forms of life. Errors occurring during DNA replication can result in mutagenesis and genome rearrangements, which can cause various diseases. In this work I have investigated the stability of direct tandem repeats (TRs) in the context of replication and replication-associated repair mechanisms. During DNA replication the replication fork encounters many obstacles, such as DNA-protein barriers, secondary DNA structures and DNA lesions. How and if replication resumes or restarts in these circumstances in order to complete genome replication is not well understood and the ?delity of replication in response to such obstacles remains unclear. I have developed TR assays to assess replication errors in the context of replication fork restart and secondary structures. The results suggest that structured DNA (G4) can cause instability of TRs in the context of normal replication and that restarted replication can be intrinsically error-prone. Surprisingly, the mutagenic effect of G4-DNA on TR stability was not elevated in the context of replication fork restart. Therefore, deletions of TRs containing G4-DNA are not more susceptible to the compromised ?delity of a restarted replication fork. Structures such as stalled replication forks can induce checkpoint responses to maintain genome stability. The stabilisation of replication forks is central in the response to replication stress. These protective mechanisms include the regulation of enzymatic activities. Mus81-Eme1 is a structurespeci?c endonuclease which is regulated by the DNA replication checkpoint, but has also been shown to be required for replication fork restart in certain circumstances. In collaboration with Professor Neil McDonald I analysed a novel domain identi?ed in Mus81-Eme1. Mutagenesis of key residues deduced from the protein structure and comparison of their genetic analysis to known phenotypes of Mus81-Eme1 suggests distinct requirements for this domain.

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  • Published version

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245.0

Department affiliated with

  • Biochemistry Theses

Qualification level

  • doctoral

Qualification name

  • dphil

Language

  • eng

Institution

University of Sussex

Full text available

  • Yes

Legacy Posted Date

2012-05-18

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