The Influence of Self-Repair on the Distribution of Cyclopyrimidine Dimers in DNA

由紫外线（UV）光引起的DNA损伤和基因突变之间的联系是公认的，但紫外线损伤最有可能发生的光化学反应热点的决定因素仍然难以捉摸。该项目将解决这些热点的起源和位置，重点是如何损害积累作为其形成和自发自我修复之间的竞争的结果。这些结果应该为未来更好地保护基因组免受紫外线损害的战略提供信息。该项目将为研究生和本科生提供跨学科的培训机会，因为他们研究影响紫外线照射下生命活力的分子过程，并为他们服务于公众利益的各种职业做好准备。双链DNA的曲率以前曾被报道为光化学损伤形成和分布的关键变量。这种属性是否控制产品的初始形成或它们的稳态水平，由竞争形成和自我修复过程建立，尚未确定。同样，DNA序列中对曲率最敏感的损伤也没有确定。这两个未知数将通过探测可以在线性和弯曲构象之间切换的DNA序列库来解决。UV损伤的可逆性将通过这两种DNA相互转化状态产生的产物谱的速率来评估，并且将通过深度测序来表征文库中受弯曲影响最大的序列。最易受紫外线损伤的序列将通过统计分析重建，并用于验证序列之间的相关性，构象和体外高反应性。这个奖项是共同的-该奖项反映了NSF的法定使命，并通过使用基金会的知识价值和更广泛的影响审查进行评估，被认为值得支持的搜索.

The link between DNA damage caused by ultraviolet (UV) light and genetic mutation is well established, but the determinants of hotspots of photochemical reactivity where UV damage is most likely to occur remain elusive. This project will address the origins and locations of these hotspots with a focus on how damage accumulates as a result of competition between its formation and spontaneous self-repair. The outcomes should inform future strategies for better protection of genomes from UV damage. The project will offer cross-disciplinary training opportunities for graduate and undergraduate students as they study molecular processes affecting the viability of life under UV exposure, and prepare them for diverse careers that serve the public interest.Curvature of duplex DNA was previously reported as a crucial variable in the formation and distribution of photochemical damage. Whether this property controls initial formation of the products or their steady state levels, established by competing formation and self-repair processes, has yet to be determined. Similarly, the sequences of DNA where damage is most sensitive to curvature have not been determined. Both of these unknowns will be addressed by probing a library of DNA sequences that can be switched between linear and bent conformations. The reversibility of UV damage will be assessed by the rate at which product profiles created by these two states of DNA interconvert, and sequences within the library most influenced by bending will be characterized by deep sequencing. The sequences most susceptible to UV damage will be reconstructed by statistical analysis and used to validate the correlation between sequence, conformation and hyperreactivity in vitro.This award was co-funded by the Division of Molecular and Cellular Biosciences and the Division of Chemistry.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.