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Mutagenesis after transfection of monkey kidney cells with acetoxyacetylaminofluorene-treated (AAAF) or depurinated simian virus 40 (SV40) DNA
179 could result in some cases in an artefactual increase in resistant colonies and could account for the apparent locus specificity of some "mutator" phenotypes.
1.2.8 Franekic, J., M. Horvat, Z. Matijasevic, V. Bacun-Druzina and M. Alacevic
The synergistic el'fects of chloroquine and MNNG or saccharin on Saccharomyces cerevisiae D7 and D6 The protein inhibitor chloroquine (CLQ) is a synthetic antimalarial agent used primarily for prophylaxis. The compounds tested were: CIQ, M N N G and saccharin. C1Q was tested for its genotoxic activity and for the synergistic activity with M N N G on mitotic crossing-over, gene conversion and mutation induction on S. cerevisiae D7 strain. CIQ by itself was neither mutagenic nor recombinogenic on strain D7. C1Q had a synergistic effect with M N N G inducing gene conversion and point mutation at a higher rate than M N N G itself. The effect of CIQ was diminished if added 15 min after M N N G and fully eliminated if added after 30 min. The effect of mitotic non-disjunction of C1Q by itself as well as together with saccharin on S. cerevisiae D6 was strong and followed a linear dose response. The effect on S. cerevisiae D6 was highest in the presence of M N N G and M N N G with CIQ. However, due to the high toxicity of M N N G and M N N G with C1Q (98%) the frequencies of mitotic aneuploidy were also extremely high, but could not be exactly established. 1.2.9 Gentil, A., A. Margot, J. Armier and A. Sarasin, I.R.S.C.-C.N.R.S., B.P. No. 8, 94802-Villejuif Cedex (France)
Mutagenesis after transfection of monkey kidney cells with acetoxyacetylaminofluorene-treated depurinated simian virus 40 (SV40) DNA
(AAAF) or
It has been shown using SV40 as a molecular probe that pretreatment of the host cell with UV light increases mutagenesis of the viral progeny of UV irradiated SV40 [1]. Under similar "SOS" conditions apurinic sites are mutagenic for ~/iX 174 DNA when transfected into E. coli [2]. We have therefore tested whether transfection of permissive monkey kidney cells under normal or "SOS" conditions either with SV40 DNA treated in vitro with another DNA-damaging agent, acetoxyacetylaminofluorene (AAAF), or with depurinated SV40 DNA gives rise to a mutated viral progeny. The number of AAAF adducts was determined using tritiated AAAF. The number of apurinic sites (AP sites) produced by heating at 70°C at p H 4.5, was determined in two ways, either using the property that AP sites are alkali labile or using the cleavage of AP sites by the T4 endonuclease. Quantification was done by Poisson analysis after agarose gel electrophoresis. Results showed that AAAF-treated or depurinated SV40 DNA gives rise to a mutated viral progeny, as measured by the reversion frequency of a thermosensitive phenotype towards a wild-type phenotype, when transfected into untreated cells. Pretreatment of the host cell with UV light 24 h before being transfected, in order to induce "SOS" response, did not increase mutagenesis.
References 1 Sarasin, A., and A. Benoit, Mutation Res., 70 (1980) 71-81. 2 Shaaper, R.M. et al., Mutation Res., 106 (1982) 1-9.
1.2.8 Franekic, J., M. Horvat, Z. Matijasevic, V. Bacun-Druzina and M. Alacevic
The synergistic el'fects of chloroquine and MNNG or saccharin on Saccharomyces cerevisiae D7 and D6 The protein inhibitor chloroquine (CLQ) is a synthetic antimalarial agent used primarily for prophylaxis. The compounds tested were: CIQ, M N N G and saccharin. C1Q was tested for its genotoxic activity and for the synergistic activity with M N N G on mitotic crossing-over, gene conversion and mutation induction on S. cerevisiae D7 strain. CIQ by itself was neither mutagenic nor recombinogenic on strain D7. C1Q had a synergistic effect with M N N G inducing gene conversion and point mutation at a higher rate than M N N G itself. The effect of CIQ was diminished if added 15 min after M N N G and fully eliminated if added after 30 min. The effect of mitotic non-disjunction of C1Q by itself as well as together with saccharin on S. cerevisiae D6 was strong and followed a linear dose response. The effect on S. cerevisiae D6 was highest in the presence of M N N G and M N N G with CIQ. However, due to the high toxicity of M N N G and M N N G with C1Q (98%) the frequencies of mitotic aneuploidy were also extremely high, but could not be exactly established. 1.2.9 Gentil, A., A. Margot, J. Armier and A. Sarasin, I.R.S.C.-C.N.R.S., B.P. No. 8, 94802-Villejuif Cedex (France)
Mutagenesis after transfection of monkey kidney cells with acetoxyacetylaminofluorene-treated depurinated simian virus 40 (SV40) DNA
(AAAF) or
It has been shown using SV40 as a molecular probe that pretreatment of the host cell with UV light increases mutagenesis of the viral progeny of UV irradiated SV40 [1]. Under similar "SOS" conditions apurinic sites are mutagenic for ~/iX 174 DNA when transfected into E. coli [2]. We have therefore tested whether transfection of permissive monkey kidney cells under normal or "SOS" conditions either with SV40 DNA treated in vitro with another DNA-damaging agent, acetoxyacetylaminofluorene (AAAF), or with depurinated SV40 DNA gives rise to a mutated viral progeny. The number of AAAF adducts was determined using tritiated AAAF. The number of apurinic sites (AP sites) produced by heating at 70°C at p H 4.5, was determined in two ways, either using the property that AP sites are alkali labile or using the cleavage of AP sites by the T4 endonuclease. Quantification was done by Poisson analysis after agarose gel electrophoresis. Results showed that AAAF-treated or depurinated SV40 DNA gives rise to a mutated viral progeny, as measured by the reversion frequency of a thermosensitive phenotype towards a wild-type phenotype, when transfected into untreated cells. Pretreatment of the host cell with UV light 24 h before being transfected, in order to induce "SOS" response, did not increase mutagenesis.
References 1 Sarasin, A., and A. Benoit, Mutation Res., 70 (1980) 71-81. 2 Shaaper, R.M. et al., Mutation Res., 106 (1982) 1-9.