Inhibition of in vitro SV40 DNA replication by ultraviolet light.
Ultraviolet light-induced DNA damage was found to inhibit SV40 origin-dependent DNA synthesis carried out by soluble human cell extracts. Replication of SV40-based plasmids was reduced to approx. 35% of that in unirradiated controls after irradiation with 50-100 J/m2 germicidal ultraviolet light, where an average of 3-6 pyrimidine dimer photoproducts were formed per plasmid circle. Inhibition of the DNA helicase activity of T antigen (required for initiation of replication in the in vitro system) was also investigated, and was only significant after much higher fluences, 1000-5000 J/m2. The data indicate that DNA damage by ultraviolet light inhibits DNA synthesis in cell-free extracts principally by affecting components of the replication complex other than the DNA helicase activity of T antigen. The soluble system could be used to biochemically investigate the possible bypass or tolerance of DNA damage during replication.
Gough
G
G
Imperial Cancer Research Fund, Clare Hall Laboratories, South Mimms, Great Britain.
Wood
R D
RD
D000952:Antigens, Polyomavirus Transforming / Q000235:genetics; D002474:Cell-Free System; D004265:DNA Helicases / Q000378:metabolism; D004261:DNA Replication / Q000528:radiation effects*; D004279:DNA, Viral / Q000096:biosynthesis* / Q000528:radiation effects; D004338:Drug Combinations; D006367:HeLa Cells; D006801:Humans; D010957:Plasmids; D013539:Simian virus 40 / Q000502:physiology* / Q000528:radiation effects; D014466:Ultraviolet Rays
D000952:Antigens, Polyomavirus Transforming; D004279:DNA, Viral; D004338:Drug Combinations; D004265:DNA Helicases