title: Apurinic sites cause mutations in simian virus 40.
abstract: SV40 has been used as a molecular probe to study the mutagenicity of apurinic sites (Ap) in mammalian cells. Untreated or UV-irradiated monkey kidney cells were transfected with depurinated DNA from the temperature-sensitive tsB201 SV40 late mutant which grows normally at the permissive temperature of 33 degrees C but which is unable to grow at 41 degrees C. Phenotypic revertants were screened at 41 degrees C for their ability to grow at the restrictive temperature and the mutation frequency was calculated in the viral progeny. Ap sites were introduced into DNA by heating at 70 degrees C under acid conditions (pH 4.8). This treatment induces one Ap site per SV40 genome per 15 min of heating as measured by alkaline denaturation or by treatment with the T4-encoded UV-specific endonuclease which possesses Ap-endonuclease activity. The experiments reported here show that Ap sites strongly decrease virus survival with a lethal hit corresponding roughly to 3 Ap lesions per SV40 genome, and indicate for the first time that apurinic sites produced by heating are highly mutagenic in animal cells. UV irradiation of the host cells 24 h prior to transfection with depurinated DNA did not modify the mutation frequency in the virus progeny.
mesh_terms: D000818:Animals; D001080:Apurinic Acid / Q000235:genetics*; D002522:Chlorocebus aethiops; D004260:DNA Repair / Q000528:radiation effects; D009154:Mutation; D011119:Polynucleotides / Q000235:genetics*; D013539:Simian virus 40 / Q000235:genetics*; D014466:Ultraviolet Rays; D014779:Virus Replication
chemical_list: D011119:Polynucleotides; D001080:Apurinic Acid