Cobaltous chloride-induced mutagenesis in the supF tRNA gene of Escherichia coli
| Autor: | H. Iyehara Ogawa, Yasuhiko Kato, Yoshihito Shirai, Yusuke Ohyama, Kohji Kakimoto, Kazuo Yamamoto, Tatsuo Nunoshibaand, Yukihide Ohsumi |
|---|---|
| Rok vydání: | 1999 |
| Předmět: |
Health
Toxicology and Mutagenesis Biology Toxicology medicine.disease_cause chemistry.chemical_compound Plasmid RNA Transfer Genetics medicine Escherichia coli Point Mutation Frameshift Mutation Genes Suppressor Gene Genetics (clinical) Mutation Models Genetic Mutagenesis Antimutagenic Agents Transfection Cobalt Sequence Analysis DNA Molecular biology chemistry Transfer RNA DNA Transposable Elements DNA Gene Deletion |
| Zdroj: | Mutagenesis. 14(2) |
| ISSN: | 0267-8357 |
| Popis: | The spectrum of mutations induced by cobalt(II) chloride (CoCl 2 ) was examined using plasmid pUB3 DNA, which was propagated after transfection into Escherichia coli SY1032/pKY241 host cells. The vector plasmid carried an E.coli supF suppressor tRNA gene as a target for mutations. After CoCl 2 treatment, 64 independent nalidixic acid-resistant, ampicillin-resistant and Lac + (SupF - ) clones were obtained and the altered sequences of the mutated supF - genes were determined. Deletions and frameshifts were the predominant mutational event (61%) induced by CoCl 2 and base substitutions were induced to a lesser degree (29%). Analysis of sequence alterations at all the sites of mutation revealed that: (i) 18 of 19 base substitutions and eight of 10 frameshifts occurred at G:C sites, suggesting that the formation of N7G-Co(II) adducts may be responsible for premutagenic lesions of these mutations; (ii) short sequence repeats were mostly found at the sites of deletions and frameshifts. Slippage-misalignment is also suggested to be a mechanism for the induction of mutations at these sites. |
| Databáze: | OpenAIRE |
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