GENE SPECIFIC DNA ADDUCTION, REPAIR, AND MUTAGENICITY OF HETEROCYCLIC AMINES

杂环胺（HA）DNA加合物如何影响诱变并不清楚。 然而，可以肯定的是，这个问题是有意义的，因为 DNA加合物和突变在致癌性中的可能作用 过程 以前，我们比较了2-氨基-1- 甲基-6-苯基咪唑[4，5-B]吡啶（PhIP）和2-氨基-3-甲基咪唑 使用修复的supF穿梭载体系统中的[4，5- f]喹啉（IQ） 缺乏和熟练的人成纤维细胞。 优势突变 诱导的是G到T颠换突变。 但有 两种HA在其突变谱中的差异，以及 突变谱受DNA修复的影响。 我们进一步检查了 突变热点与加合物之间是否存在相关性 热点 聚合酶阻滞试验热循环测序， 开发用于测量特定基因中的IQ和PhIP加合物水平 顺序 应用该方法研究了中国大学生的智商水平和PhIP水平 supF基因中的加合物。 发现IQ和PhIP加合物仅形成 在supF基因的鸟嘌呤碱基上，以及IQ和PhIP的分布 加合物相似。 值得注意的是，加合物热点与 变种火锅 这些发现强调加合物热点不是 不可避免地突变热点，并且进一步地，相对低的加合物 在突变热点处诱导突变所需的水平。

Just how heterocyclic amine (HA) DNA adducts influence mutagenesis is not known with certainty, however, this question is of interest in light of the possible role of DNA adducts and mutations in the carcinogenic process. Previously, we compared the mutation spectra of 2-amino-1- methyl-6-phenylimidazo[4,5-b]pyridine (PhIP) and 2-amino-3-methylimidazo [4,5- f]quinoline (IQ)in the supF shuttle vector system using repair deficient and proficient human fibroblasts. The predominant mutation induced was a G to T transversion mutation. However, there were differences between the two HAs in their mutation spectra, and the mutation spectra were influenced by DNA repair. We further examined whether there was a correlation between mutation hotspots and adduct hotspots. A polymerase arrest assay thermal cycle sequencing was developed to measure the levels of IQ and PhIP adducts in defined gene sequence. This method was applied to study the levels of IQ and PhIP adducts in the supF gene. IQ and PhIP adducts were found to form only at the guanine base in the supF gene, and the distribution of IQ and PhIP adducts was similar. Notably, adduct hotspots did not correlate with mutation hotpots. These findings emphasize that adduct hotspots are not necessarily mutation hotspots and further that relatively low adduct levels are needed to induce mutations at mutation hotspots.