Next-generation sequencing reveals the biological significance of the N[superscript 2],3-ethenoguanine lesion in vivo

• Main Authors: Chang, Shiou-chi (Contributor), Wu, Jie (Contributor), Delaney, James C. (Contributor), Li, Deyu (Contributor), Zhao, Linlin (Author), Christov, Plamen P. (Author), Yau, Emily (Contributor), Singh, Vipender (Contributor), Jost, Marco (Author), Marnett, Lawrence J. (Author), Rizzo, Carmelo J. (Author), Levine, Stuart S. (Contributor), Guengerich, F. Peter (Author), Essigmann, John M. (Contributor), Drennan, Catherine L (Author), Fedeles, Bogdan I (Author)
• Other Authors: Massachusetts Institute of Technology. Center for Environmental Health Sciences (Contributor), Massachusetts Institute of Technology. Department of Biological Engineering (Contributor), Massachusetts Institute of Technology. Department of Biology (Contributor), Massachusetts Institute of Technology. Department of Chemical Engineering (Contributor), Massachusetts Institute of Technology. Department of Chemistry (Contributor), Drennan, Catherine L. (Contributor), Fedeles, Bogdan I. (Contributor)
• Format: Article
• Language: English
• Published: Oxford University Press, 2015-04-08T16:21:52Z.
• Subjects: Article
• Online Access: Get fulltext

 Etheno DNA adducts are a prevalent type of DNA damage caused by vinyl chloride (VC) exposure and oxidative stress. Etheno adducts are mutagenic and may contribute to the initiation of several pathologies; thus, elucidating the pathways by which they induce cellular transformation is critical. Although N[superscript 2],3-ethenoguanine (N[superscript 2],3-εG) is the most abundant etheno adduct, its biological consequences have not been well characterized in cells due to its labile glycosidic bond. Here, a stabilized 2'-fluoro-2'-deoxyribose analog of N[superscript 2],3-εG was used to quantify directly its genotoxicity and mutagenicity. A multiplex method involving next-generation sequencing enabled a large-scale in vivo analysis, in which both N[superscript 2],3-εG and its isomer 1,N[superscript 2]-ethenoguanine (1,N[superscript 2]-εG) were evaluated in various repair and replication backgrounds. We found that N[superscript 2],3-εG potently induces G to A transitions, the same mutation previously observed in VC-associated tumors. By contrast, 1,N[superscript 2]-εG induces various substitutions and frameshifts. We also found that N[superscript 2],3-εG is the only etheno lesion that cannot be repaired by AlkB, which partially explains its persistence. Both εG lesions are strong replication blocks and DinB, a translesion polymerase, facilitates the mutagenic bypass of both lesions. Collectively, our results indicate that N[superscript 2],3-εG is a biologically important lesion and may have a functional role in VC-induced or inflammation-driven carcinogenesis.