Disentangling strand interactions in DNA damage and repair

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• Sarah Aitken, MRC Toxicology Unit
• Tuesday 18 October 2022, 12:30-13:30
• Lecture Theatre, Department of Pathology, Tennis Court Road.

If you have a question about this talk, please contact Michael Boemo.

Cancers arise through the acquisition of oncogenic mutations and grow by clonal expansion. Here we reveal that most mutagenic DNA lesions are not resolved into a mutated DNA base pair within a single cell cycle. Instead, DNA lesions segregate, unrepaired, into daughter cells for multiple cell generations, resulting in the chromosome-scale phasing of subsequent mutations. Furthermore, DNA replication across these persisting lesions can produce multiple alternative alleles in successive cell divisions, thereby generating both multiallelic and combinatorial genetic diversity. We exploit our discovery of lesion segregation to reveal how strand-asymmetric processes such as replication, transcription, and protein interactions shape DNA damage and repair. We demonstrate that replication over lesions produces almost identical collateral mutagenesis on the leading and lagging strands. In transcription, the triggering of repair is stochastic with frequent lesion bypass by RNA -polymerase. Finally, defining multiallelic variation patterns, we examine patterns of mutations in accessible chromatin regions as well as transcription factor binding sites. These results provide insight into how strand asymmetric mechanisms underlie the formation, tolerance, and repair of DNA damage and thus shape cancer genome evolution.

This talk is part of the Cellular and Molecular Pathology Seminars series.

This talk is included in these lists:

• Cellular and Molecular Pathology Seminars
• Lecture Theatre, Department of Pathology, Tennis Court Road

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