Quantification of Intracellular DNA-Protein Cross-Links with N7-Methyl-2'-Deoxyguanosine and Their Contribution to Cytotoxicity.

Autor: Wen T; Department of Chemistry, Johns Hopkins University, 3400 N. Charles St., Baltimore, Maryland 21218, United States., Zhao S; Gene Center and Department of Biochemistry, Ludwig-Maximilians-Universität München, 81377 Munich, Germany., Stingele J; Gene Center and Department of Biochemistry, Ludwig-Maximilians-Universität München, 81377 Munich, Germany., Ravanat JL; Univ. Grenoble Alpes, CEA, CNRS, Grenoble INP, IRIG, SyMMES, 38000 Grenoble, France., Greenberg MM; Department of Chemistry, Johns Hopkins University, 3400 N. Charles St., Baltimore, Maryland 21218, United States.
Jazyk: angličtina
Zdroj: Chemical research in toxicology [Chem Res Toxicol] 2024 May 20; Vol. 37 (5), pp. 814-823. Date of Electronic Publication: 2024 Apr 23.
DOI: 10.1021/acs.chemrestox.4c00076
Abstrakt: The major product of DNA-methylating agents, N7-methyl-2'-deoxyguanosine (MdG), is a persistent lesion in vivo , but it is not believed to have a large direct physiological impact. However, MdG reacts with histone proteins to form reversible DNA-protein cross-links (DPC MdG ), a family of DNA lesions that can significantly threaten cell survival. In this paper, we developed a tandem mass spectrometry method for quantifying the amounts of MdG and DPC MdG in nuclear DNA by taking advantage of their chemical lability and the concurrent release of N7-methylguanine. Using this method, we determined that DPC MdG is formed in less than 1% yield based upon the levels of MdG in methyl methanesulfonate (MMS)-treated HeLa cells. Despite its low chemical yield, DPC MdG contributes to MMS cytotoxicity. Consequently, cells that lack efficient DPC repair by the DPC protease SPRTN are hypersensitive to MMS. This investigation shows that the downstream chemical and biochemical effects of initially formed DNA damage can have significant biological consequences. With respect to MdG formation, the initial DNA lesion is only the beginning.
Databáze: MEDLINE