DNA lesion bypass and the stochastic dynamics of transcription- coupled repair

• 成果类型: Article
• 署名作者: Nicholson, Michael D.; Anderson, Craig J.; Odom, Duncan T.; Aitken, Sarah J.; Taylor, Martin S.
• 署名单位: University of Edinburgh; University of Edinburgh; Helmholtz Association; German Cancer Research Center (DKFZ); University of Cambridge; Cancer Research UK; CRUK Cambridge Institute; UK Research & Innovation (UKRI); Medical Research Council UK (MRC); University of Cambridge; University of Cambridge
• 刊物名称: PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
• ISSN/ISSBN: 0027-11380
• DOI: 10.1073/pnas.2403871121
• 发表日期: 2024-05-14
• 关键词: rna-polymerase-ii; gene-expression; single-cell; damage

摘要

DNA base damage is a major source of oncogenic mutations and disruption to gene expression. The stalling of RNA polymerase II (RNAP) at sites of DNA damage and the subsequent triggering of repair processes have major roles in shaping the genome - wide distribution of mutations, clearing barriers to transcription, and minimizing the production of miscoded gene products. Despite its importance for genetic integrity, key mechanistic features of this transcription - coupled repair (TCR) process are controversial or unknown. Here, we exploited a well - powered in vivo mammalian model system to explore the mechanistic properties and parameters of TCR for alkylation damage at fine spatial resolution and with discrimination of the damaged DNA strand. For rigorous interpretation, a generalizable mathematical model of DNA damage and TCR was developed. Fitting experimental data to the model and simulation revealed that RNA polymerases frequently bypass lesions without triggering repair, indicating that small alkylation adducts are unlikely to be an efficient barrier to gene expression. Following a burst of damage, the efficiency of transcription - coupled repair gradually decays through gene bodies with implications for the occurrence and accurate inference of driver mutations in cancer. The reinitation of transcription from the repair site is not a general feature of transcription - coupled repair, and the observed data is consistent with reinitiation never taking place. Collectively, these results reveal how the directional but stochastic activity of TCR shapes the distribution of mutations following DNA damage.