Mechanism of mutation on DNA templates containing synthetic abasic sites: study with a double strand vector.

AUTOR(ES)

Takeshita, M

RESUMO

Mutagenesis at abasic sites was investigated in E.coli and simian kidney (COS) cells using a duplex shuttle vector containing synthetic analogs of deoxyribose on the phosphodiester backbone. Lesions were positioned on opposite strands of the vector. When the tetrahydrofuranyl analog was used as the abasic site, AT or TA pairs (65-80%) were introduced at the site of the bistrand lesion. Mutagenesis occurred in the absence of SOS induction. Single base deletions (> 80%) dominated the mutational spectra for propanyl and ethanyl analogs of abasic sites lacking a ring structure. For all abasic site analogs, a small proportion of G/C and C/G pairs (6-10%) were observed. dAMP was incorporated predominantly opposite tetrahydrofuranyl sites positioned in the single strand region of a gapped duplex vector. We conclude from these studies that abasic sites positioned in a bistrand configuration are highly mutagenic in E.coli and COS cells. Repair DNA synthesis may be involved in this process.

Documentos Relacionados

• The acridine ring selectively intercalated into a DNA helix at various types of abasic sites: double strand formation and photophysical properties.
• Oligodeoxynucleotides containing conformationally constrained abasic sites: a UV and fluorescence spectroscopic investigation on duplex stability and structure
• Mutation frequency and spectrum resulting from a single abasic site in a single-stranded vector.
• Induction of double-strand breaks by S1 nuclease, mung bean nuclease and nuclease P1 in DNA containing abasic sites and nicks.
• Effects of abasic sites and DNA single-strand breaks on prokaryotic RNA polymerases.