Vaisman A, Lim S E, Patrick S M, Copeland W C, Hinkle D C, Turchi J J, Chaney S G
Department of Biochemistry and Biophysics, Lineberger Comprehensive Cancer Center, School of Medicine, University of North Carolina, Chapel Hill 27599-7260, USA.
Biochemistry. 1999 Aug 24;38(34):11026-39. doi: 10.1021/bi9909187.
Translesion synthesis past Pt-DNA adducts can affect both the cytotoxicity and mutagenicity of the platinum adducts. We have shown previously that the extent of replicative bypass in vivo is influenced by the carrier ligand of platinum adducts. The specificity of replicative bypass may be determined by the DNA polymerase complexes that catalyze translesion synthesis past Pt-DNA adducts and/or by DNA damage-recognition proteins that bind to the Pt-DNA adducts and block translesion replication. In the present study, primer extension on DNA templates containing site-specifically placed cisplatin, oxaliplatin, JM216, or chlorodiethylenetriamine-Pt adducts revealed that the eukaryotic DNA polymerases beta, zeta, gamma, and human immunodeficiency virus type 1 reverse transcriptase (HIV-1 RT) had a similar specificity for translesion synthesis past Pt-DNA adducts (dien >> oxaliplatin >/= cisplatin > JM216). Primer extension assays performed in the presence of high mobility group protein 1 (HMG1), which is known to recognize cisplatin-damaged DNA, revealed that inhibition of translesion synthesis by HMG1 also depended on the carrier ligand of the Pt-DNA adduct (cisplatin > oxaliplatin = JM216 >> dien). These data were consistent with the results of gel-shift experiments showing similar differences in the affinity of HMG1 for DNA modified with the different platinum adducts. Our studies show that both DNA polymerases and damage-recognition proteins can impart specificity to replicative bypass of Pt-DNA adducts. This information may serve as a model for further studies of translesion synthesis.
跨越铂 - DNA加合物的跨损伤合成会影响铂加合物的细胞毒性和致突变性。我们之前已经表明，体内复制性绕过的程度受铂加合物载体配体的影响。复制性绕过的特异性可能由催化跨越铂 - DNA加合物的跨损伤合成的DNA聚合酶复合物和/或由与铂 - DNA加合物结合并阻断跨损伤复制的DNA损伤识别蛋白决定。在本研究中，对含有位点特异性放置的顺铂、奥沙利铂、JM216或氯二乙三胺 - 铂加合物的DNA模板进行引物延伸，结果显示真核DNA聚合酶β、ζ、γ和人类免疫缺陷病毒1型逆转录酶（HIV - 1 RT）对跨越铂 - DNA加合物的跨损伤合成具有相似的特异性（二乙三胺 >> 奥沙利铂 ≥ 顺铂 > JM216）。在已知能识别顺铂损伤DNA的高迁移率族蛋白1（HMG1）存在下进行的引物延伸试验表明，HMG1对跨损伤合成的抑制也取决于铂 - DNA加合物的载体配体（顺铂 > 奥沙利铂 = JM216 >> 二乙三胺）。这些数据与凝胶迁移实验结果一致，该实验显示HMG1对用不同铂加合物修饰的DNA的亲和力存在类似差异。我们的研究表明，DNA聚合酶和损伤识别蛋白都可以赋予铂 - DNA加合物复制性绕过的特异性。这些信息可作为进一步研究跨损伤合成的模型。
