DNA Adducts of Styrene and Other Vinyl Monomers

描述（由申请人提供）：用于橡胶和塑料生产的苯乙烯和丁二烯与人类癌症的病因有关。美国环保局将丁氨酰列为“吸入对人类致癌物”，NTP将其列为“已知的人类致癌物”。长期职业接触苯乙烯和丁二烯混合物与白血病风险相关。本项目将研究丁二烯诱发突变的病因学，开发丁二烯环氧化物产生的DNA加合物的结构-活性关系，并与人类遗传毒性相关。第一个目标将结合联合收割机核磁共振，晶体学和生物化学的方法来检查N1-脱氧肌苷加合物所产生的脱氨基的N1-脱氧腺苷烷基化产物。我们提出了Y家族Pol i利用dl的Hoogsteen面进行模板化的作用，允许掺入质子化的dCTP或dATP。第二个目标将采用NMR和晶体学方法来检查丁二烯单环氧化物的立体异构N3-dU加合物，其产生于N3-dC加合物的脱氨基。我们认为它们不会围绕糖基键旋转成顺式构象，从而导致根本不同的生物学和致突变结果。第三个目标将使用核磁共振，生物化学，和位点特异性诱变检查N7-dG加合物所产生的暴露于丁二烯环氧化物。重点将放在N7-dG加合丁二烯二环氧化物形成链间和链内交联的关系，这取决于DNA序列和二环氧化物的立体化学。链间交联在5 '-GNC-3'序列中形成。我们建议，N7-dG丁二烯二醇环氧化物单加合物的取向取决于立体化学，差异取向的二醇环氧化物链间与链内交联。将检查N7-dG FAPy重排产物的化学、突变谱和复制旁路。总之，我们将描述N1-dl和N3-dU丁二烯加合物诱导突变的机制，以及为什么特异性聚合酶介导病变旁路。深入了解丁二烯二环氧化物的DNA交联化学。深入了解丁二烯N7-dG FAPy病变的化学，它们的生物加工和它们的结构。这对于了解苯乙烯和丁二烯混合物的职业暴露如何导致人类遗传毒性和癌症病因学至关重要。

DESCRIPTION (provided by applicant): Styrene and butadiene, used in the production of rubber and plastics, are implicated in the etiology of human cancer. Butadiene is classified by the USEPA as "carcinogenic to humans by inhalation", by the NTP as a "known human carcinogen". Chronic occupational exposures to mixtures of styrene and butadiene correlate with risk for leukemias. This project will examine the etiology of butadiene-induced mutagenesis, developing structure-activity relationships for DNA adducts arising from butadiene epoxides and associated with human genotoxicity. The first aim will combine NMR, crystallography, and biochemical approaches to examine N1- deoxyinosine adducts arising from deamination of N1-deoxyadenosine alkylation products. We propose a role for Y-family Pol i utilizing the Hoogsteen face of dl for templating, allowing incorporation of protonated dCTP or dATP. The second aim will employ NMR and crystallographic approaches to examine stereoisomeric N3-dU adducts of butadiene monoepoxide, which arise from deamination of N3-dC adducts. We propose that they do not undergo rotation about the glycosyl bond, into the syn conformation, thus leading to fundamentally different biological and mutagenic outcomes. The third aim will use NMR, biochemical, and site-specific mutagenesis to examine N7-dG adducts arising from exposures to butadiene epoxides. Emphasis will be placed on relationships of N7-dG adduction to the formation of interstrand and intrastrand crosslinks by butadiene diepoxide; this depends upon DNA sequence and diepoxide stereochemistry. Interstrand crosslinks form in 5'-GNC-3' sequences. We propose that the orientations of N7-dG butadiene diol epoxide mono-adducts depend upon stereochemistry, differentially orienting the diol epoxides for interstrand vs. intrastrand crosslinking. The chemistry, mutational spectra, and replication bypass of N7-dG FAPy re-arrangement products will be examined. Overall, we will delineate mechanism(s) by which N1-dl and N3-dU butadiene adducts induce mutations, and why specific polymerase(s) mediate lesion bypass. Insight will be gained into DNA crosslinking chemistry of butadiene diepoxides. Insight will be gained into the chemistry of butadiene N7-dG FAPy lesions, their biological processing, and their structures. This is essential to understanding how occupational exposures to mixtures of styrene and butadiene contribute to human genotoxicity and cancer etiology.