Department of Surgery
Carcinoma, Squamous Cell; DNA Packaging; DNA Repair; DNA-Binding Proteins; Gene Expression Regulation, Neoplastic; Genome, Human; Germ Cells; Heterochromatin; Humans; *Mutation Rate; Proto-Oncogene Proteins; Skin Neoplasms; *Transcription, Genetic
Bioinformatics | Cancer Biology | Computational Biology | Genetics | Genomics | Neoplasms
Somatic mutations in cancer are more frequent in heterochromatic and late-replicating regions of the genome. We report that regional disparities in mutation density are virtually abolished within transcriptionally silent genomic regions of cutaneous squamous cell carcinomas (cSCCs) arising in an XPC(-/-) background. XPC(-/-) cells lack global genome nucleotide excision repair (GG-NER), thus establishing differential access of DNA repair machinery within chromatin-rich regions of the genome as the primary cause for the regional disparity. Strikingly, we find that increasing levels of transcription reduce mutation prevalence on both strands of gene bodies embedded within H3K9me3-dense regions, and only to those levels observed in H3K9me3-sparse regions, also in an XPC-dependent manner. Therefore, transcription appears to reduce mutation prevalence specifically by relieving the constraints imposed by chromatin structure on DNA repair. We model this relationship among transcription, chromatin state, and DNA repair, revealing a new, personalized determinant of cancer risk.
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DOI of Published Version
Cell Rep. 2014 Nov 20;9(4):1228-34. doi: 10.1016/j.celrep.2014.10.031. Epub 2014 Nov 20. Link to article on publisher's site.
Zheng, Christina L.; Fudem, Gary M.; Purdom, Elizabeth; and Cho, Raymond J., "Transcription restores DNA repair to heterochromatin, determining regional mutation rates in cancer genomes" (2014). Open Access Articles. 2581.
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This work is licensed under a Creative Commons Attribution 3.0 License.