Singlet oxygen-induced DNA damage: product analysis, studies of biological consequences and characterization of mutations.
The DNA lesions induced by free 1O2 and the biological and mutagenic consequences of 1O2-induced DNA damage have been studied. Using anion exchange HPLC, reverse-phase HPLC with electrochemical detection and 32P-postlabelling methods, we have shown that 1O2 reacts with 2'-deoxyguanine 3'-monophosphate (dGp) but not with any other dNp. Reaction with dGp yields a large number of products; one minor product was identified as 7-hydro-8-oxo-2'-deoxyguanosine 3'-monophosphate (8-oxo-dGp), and a second tentatively as a formamidopyridine derivative of dGp. 8-Oxo-dGp was also found after reaction of 1O2 with single-stranded (ss) DNA, double-stranded (ds) DNA or an oligonucleotide (16-mer) having one G. With the oligonucleotide we found a second unidentified reaction product. With ss DNA, 8-oxo-dG was a much more prominent product than in the reaction of 1O2 with free dGp and the yield was about eight-fold higher than with ds DNA. This agrees with our finding that ss M13 DNA is at least 100-fold more sensitive than ds M13 DNA to biological inactivation by 1O2. The inactivation of ss M13 DNA must be largely due to 1O2-induced lesions other than 8-oxo-dG. In agreement with the observed preferential reaction of 1O2 with dG, most of the mutations induced by 1O2 in ss or ds M13mp10 DNA occurred at a G or G/C basepair, respectively. A preference for G(C) to T(A) transversions was observed for which 8-oxo-dG might have been responsible. In ss DNA, a significant number of mutations are characterized by the fact that a G is deleted.
Lutgerink
J T
JT
Department of Health Risk Analysis and Toxicology, University of Limburg, Maastricht, The Netherlands.
van den Akker
E
E
Pachen
D
D
Smeets
E J
EJ
van Dijk
P
P
Aubry
J M
JM
Joenje
H
H
Lafleur
M V
MV
Retèl
J
J
D017104:Bacteriophage M13 / Q000187:drug effects / Q000235:genetics; D001483:Base Sequence; D002855:Chromatography, Thin Layer; D004247:DNA / Q000032:analysis / Q000187:drug effects / Q000235:genetics; D004249:DNA Damage; D004252:DNA Mutational Analysis; D004279:DNA, Viral / Q000187:drug effects / Q000235:genetics; D066298:In Vitro Techniques; D008969:Molecular Sequence Data; D010100:Oxygen / Q000633:toxicity*; D010761:Phosphorus Radioisotopes; D026082:Singlet Oxygen
D004279:DNA, Viral; D010761:Phosphorus Radioisotopes; D026082:Singlet Oxygen; D004247:DNA; D010100:Oxygen