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Direct and indirect effects of UV radiation on DNA and its components
J L Ravanat1, T Douki, J Cadet
1Laboratoire Lésions des Acides Nucléiques, Service de Chimie Inorganique et Biologique, UMR 5046, Département de Recherche Fondamentale sur la Matière Condensée, CEA Grenoble, 17 Avenue des Martyrs, F-38054 Grenoble Cedex 9, France.
Abstract:
In this survey, emphasis was placed on the main photoreactions of nucleic acid components, involving both direct and indirect effects. The main UVB- and UVA-induced DNA photoproducts, together with the mechanisms of their formation, are described. Information on the photoproduct distribution within cellular DNA is also provided, taking into account the limitations of the different analytical methods applied to monitor the formation of the DNA damage. Thus, the formation of the main DNA dimeric pyrimidine lesions produced by direct absorption of UVB photons was assessed using a powerful HPLC-tandem mass spectrometry assay. In addition, it was found that UVA photooxidation damage mostly involves the guanine residues of cellular DNA as the result of singlet oxygen generation by still unknown endogenous photosensitizers.