Next-generation sequencing reveals the biological significance of the N[superscript 2],3-ethenoguanine lesion in vivo
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. Althou...
| Main Authors: | , , , , , , , , , , , , , , , |
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| Other Authors: | |
| Format: | Article |
| Language: | en_US |
| Published: |
Oxford University Press
2015
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| Online Access: | http://hdl.handle.net/1721.1/96431 https://orcid.org/0000-0002-0989-8115 https://orcid.org/0000-0001-5486-2755 https://orcid.org/0000-0001-6159-0778 https://orcid.org/0000-0002-8241-4834 https://orcid.org/0000-0002-2196-5691 https://orcid.org/0000-0002-2494-7763 |
| Summary: | 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. |
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