Abstract
We have studied mutagenic specificities of DNA lesions in vivo in yeast CYC1 oligonucleotide transformation assay. We introduced two lesions into oligonucleotides. One was a nucleoside analog, 3,4-dihydro-6H,8H-pyrimido[4,5-c][1,2]oxazin-7-one 2′-deoxyriboside (dP), which is highly mutagenic to bacteria. It is supposed to be a miscoding, but otherwise good template for DNA polymerases. The other lesion was the TT pyrimidine(6-4)pyrimidone photoproduct, one of the typical UV lesions, which blocks DNA replication. These oligonucleotides were used to transform yeast cyc1 mutants with ochre nonsense mutation to Cyc1+. As expected from its templating properties in vitro, the transforming activity of dP-containing oligonucleotides was similar to those of unmodified oligonucleotides. Results indicated that dP may direct incorporation of guanine and adenine at a ratio of 1:20 or more in vivo. An oligonucleotide containing the photoproduct showed the transforming activity of as low as 3-5% of that of the corresponding unmodified oligonucleotide. This bypass absolutely required REV1 gene. The sequence analysis of the transformants has shown that the lesion was read as TT and TC at a ratio of 3:7, indicating its high mutagenic potential.
Original language | English (US) |
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Pages (from-to) | 53-60 |
Number of pages | 8 |
Journal | Mutation Research - Fundamental and Molecular Mechanisms of Mutagenesis |
Volume | 502 |
Issue number | 1-2 |
DOIs | |
State | Published - May 22 2002 |
Externally published | Yes |
Keywords
- (6-4)Photoproduct
- Nucleoside analog
- Oligonucleotide transformation
- REV1
- Saccharomyces cerevisiae
ASJC Scopus subject areas
- Molecular Biology
- Genetics
- Health, Toxicology and Mutagenesis