SINGLET OXYGEN INDUCED DNA DAMAGE AND MUTAGENICITY IN A SINGLE-STRANDED SV40-BASED SHUTTLE VECTOR

Authors

  • D. T. Ribeiro,

    1. Departamento de Biologia, Instituto de Biocihcias, CP No. 11461, Universidade de Sêo Paulo, Sáo Paulo 05499, Brazil
    2. Departamento de Biologia Celular, Instituto de Biologia, Universidade de Brasilia, Brasilia, Brazil
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  • C. Madzak,

    1. Laboratoire de Génétique Moleculaire, Institute de Recherches Scientifiques sur le Cancer, Centre National de la Recherche Scientifique, BP No. 08, 94801 Villejuif, France
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  • A. Sarasin,

    1. Laboratoire de Génétique Moleculaire, Institute de Recherches Scientifiques sur le Cancer, Centre National de la Recherche Scientifique, BP No. 08, 94801 Villejuif, France
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  • P. DI Mascio,

    1. Institute für Physiologische Chemie I, University of Düsseldorf, Moorenstrasse 5, D-4000 Düsseldorf, Fed. Rep. Germany
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    • *Institute de Quimica, CP 20780, USP, Sáo Paulo 05499, SP, Brazil.

  • H. Sies,

    1. Institute für Physiologische Chemie I, University of Düsseldorf, Moorenstrasse 5, D-4000 Düsseldorf, Fed. Rep. Germany
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  • C. F. M. Menck

    Corresponding author
    1. Departamento de Biologia, Instituto de Biocihcias, CP No. 11461, Universidade de Sêo Paulo, Sáo Paulo 05499, Brazil
      †To whom correspondence should be addressed.
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†To whom correspondence should be addressed.

Abstract

Abstract— 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.

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