EXOCYCLIC ADDUCTS--SITE-SPECIFIC MUTAGENESIS

这项研究的目的是确定人的突变谱 外环加合物在哺乳动物细胞和细菌中产生的损伤 在特定的基因组位置引入，并描绘出重组 与这种加合物产生的诱变有关的事件。 DNA加合物可以通过修复酶的协同作用而被移除 在整个基因组中。当这一过程完成时，舞台就设置好了 导致突变的DNA复制错误。我们打算投资- 滴定DNA修复的几个方面，因为它与结构和 外环加合物的功能。 我们已经开发了实验系统，使用基于SV40的穿梭质粒 载体，通过该载体，选定的DNA加合物的诱变光谱可以 下定决心。这种方法使我们能够检查序列的特异性 突变反应，特别涉及“热点”和原生生物- 致癌基因。使用这些反映前向突变事件的系统 由单一物种的DNA加合物产生，并通过将我们的研究关联起来 根据分子模拟和2D-核磁共振实验的结果，我们希望 确定有助于阐明的结构-活性关系 化学诱变的机制及其可能预测的诱变效应 对于某些类别的化学致癌物。

The objectives of this research are to determine the mutational spectra of lesions produced in mammalian cells and bacteria when exocyclic adducts are introduced at specific genomic sites and to delineate recombinational events as they relate to mutagenesis produced by such adducts. DNA adducts may be removed by the concerted action of repair enzymes acting throughout the genome. When this process is incomplete, the stage is set for errors in DNA replication that lead to mutation. We intend to inves- tigate several aspects of DNA repair as it relates to the structure and function of exocyclic adducts. We have developed experimental systems, using SV40-based shuttle plasmid vectors, by which the mutagenic spectra of selected DNA adducts can be determined. This approach allows us to examine the sequence specificity of mutational reactions with particular reference to "hot spots" and proto- oncogenes. Using these systems, which reflect forward mutagenic events produced by a single species of DNA adduct and by correlating our studies with the results of molecular modeling and 2D-NMR experiments, we hope to define structure-activity relationships that will assist in elucidating mechanisms of chemical mutagenesis and, possibly, predict mutagenic effects for certain classes of chemical carcinogens.