2-(N-acetoxy-N-acetylamino)fluorene mutagenesis in mammalian cells: sequence-specific hot spot.

AUTOR(ES)

Gentil, A

RESUMO

Mutations induced by 2-(N-acetoxy-N-acetylamino)fluorene were studied using temperature-sensitive simian virus 40 (SV40) mutants as probe in monkey kidney cells. In vitro treatment of the SV40 virions with 2-(N-acetoxy-N-acetylamino)fluorene increased mutagenesis and decreased survival in the viral progeny. A lethal hit of approximately 85 acetylaminofluorene adducts per SV40 genome was calculated. UV irradiation of cells prior to infection did not modify the results. Molecular analysis of independent SV40 revertants showed that 2-(N-acetoxy-N-acetylamino)fluorene induces base substitutions that are located not opposite putative acetylaminofluorene adducts but next to them. Moreover, a hot spot of mutation restoring a true wild-type genotype was observed in 10 of the 16 revertants analyzed. This hot spot, not targeted opposite a major DNA lesion, was not observed using UV light as damaging agent in the same genetic assay. Two models involving the stabilization, by acetylaminofluorene adducts, of the secondary structure of a specific quasipalindromic SV40 sequence are proposed to explain this sequence-specific hot spot.

Documentos Relacionados

• A method for sequence-specific deletion mutagenesis.
• Short hairpin RNAs (shRNAs) induce sequence-specific silencing in mammalian cells
• Sequence-specific affinity selection of mammalian splicing complexes.
• Sequence-specific responses of restriction endonucleases to bromodeoxyuridine substitution in mammalian DNA.
• Characterization of mutations induced by 2-(N-acetoxy-N-acetyl)aminofluorene in the dihydrofolate reductase gene of cultured hamster cells.