Singlet oxygen induced DNA damage and mutagenicity in a single-stranded SV40-based shuttle vector.
The effects of singlet oxygen (1O2), generated by the thermal decomposition of water soluble NDPO2 (endoperoxide of the disodium 3,3'-(1,4-naphthylidene) dipropionate), on a single-stranded shuttle vector were analysed. 1O2 induces a much higher level of breaks in the phosphodiester backbone of single-stranded than double-stranded DNA. This may be due to a higher accessibility of guanine residue, primarily damaged by 1O2. The damaged vector was transfected into monkey COS7 cells where single-stranded DNA was converted to the double-stranded replicative form DNA. After 3 days, extrachromosomal DNA was extracted and the plasmids rescued in E. coli to study mutagenesis. There is a significant increase in mutation frequency of damaged single-stranded DNA in comparison to untreated DNA. It is concluded that 1O2 induces breaks in the backbone of single-stranded DNA and that the 1O2-damaged molecules are mutated after passage through mammalian cells.
Ribeiro
D T
DT
Departamento de Biologia, Universidade de São Paulo, Brazil.
Madzak
C
C
Sarasin
A
A
Di Mascio
P
P
Sies
H
H
Menck
C F
CF
D000818:Animals; D002460:Cell Line; D015500:Chloramphenicol O-Acetyltransferase / Q000235:genetics / Q000378:metabolism; D004249:DNA Damage; D004277:DNA, Single-Stranded / Q000235:genetics / Q000528:radiation effects*; D004926:Escherichia coli / Q000235:genetics; D005822:Genetic Vectors; D016296:Mutagenesis; D010100:Oxygen / Q000494:pharmacology*; D010777:Photochemistry; D013539:Simian virus 40 / Q000235:genetics*; D026082:Singlet Oxygen; D014162:Transfection
D004277:DNA, Single-Stranded; D026082:Singlet Oxygen; D015500:Chloramphenicol O-Acetyltransferase; D010100:Oxygen