Replication of N2-ethyldeoxyguanosine DNA adducts in the human embryonic kidney cell line 293.
Replication of N2-ethyldeoxyguanosine DNA adducts in the human embryonic kidney cell line 293.
复制标题
N2-乙基脱氧鸟苷 DNA 加合物在人胚胎肾细胞系 293 中的复制。
DOI：
10.1021/tx060084a
复制
发表时间：
2006
影响因子：
4.1
通讯作者：
Akman,StevenA
中科院分区：
文献类型：
--
作者：
Upton,DanaC;Wang,Xueying;Blans,Patrick;Perrino,FredW;Fishbein,JamesC;Akman,StevenA
N2-Ethyldeoxyguanosine (N2-ethyldGuo) is a DNA adduct formed by reaction of the exocyclic amine of dGuo with the ethanol metabolite acetaldehyde. Because ethanol is a human carcinogen, we assessed the biological consequences of replication of template N2-ethyldGuo, in comparison to the well-studied adduct O6-ethyldeoxyguanosine (O6-ethyldGuo). Single chemically synthesized N2-ethyldGuo or O6-ethyldGuo adducts were placed site specifically in the suppressor tRNA gene of the mutation reporting shuttle plasmid pLSX. N2-EthyldGuo and O6-ethyldGuo were both minimally mutagenic in double-stranded pLSX replicated in human 293 cells; however, the placement of deoxyuridines on the complementary strand at 5‘- and 3‘-positions flanking the adduct resulted in 5- and 22-fold enhancements of the N2-ethyldGuo- and O6-ethyldGuo-induced mutant fractions, respectively. The fold increase in the N2-ethyldGuo-induced mutant fraction in deoxyuridine-containing plasmids was similar after replication in 293T cells, a mismatch repair deficient variant of 293 cells, indicating that postreplication mismatch repair has little role in modulating N2-ethyldGuo-mediated mutagenesis. The mutation spectrum generated by N2-ethyldGuo consisted primarily of single base deletions and adduct site-targeted transversions, in contrast to the exclusive production of adduct site-targeted transitions by O6-ethyldGuo. The yield of progeny plasmids after replication in 293 cells was reduced by the presence of N2-ethyldGuo in parental plasmids with or without deoxyuridine to 39 or 19%, respectively. Taken together, these data indicate that N2-ethyldGuo in DNA exerts its principal biological activity by blocking translesion DNA synthesis in human cells, resulting in either failure of replication or frameshift deletion mutations.
