Anti-mutagenic effect of ultraviolet light on spontaneous tyrosine tRNA ochre suppressor mutations in Escherichia coli
- 1 October 1988
- journal article
- research article
- Published by Springer Nature in Molecular Genetics and Genomics
- Vol. 214 (2), 361-364
- https://doi.org/10.1007/bf00337737
Abstract
The numbers of tyrosine tRNA ochre suppressor mutations arising spontaneously or after UV irradiation in different strains of Escherichia coli K12 are considered. The DNA sequence change requisite for this type of mutation would be a transversion at a cytosine between two purines, where pyrimidine-pyrimidine photoproducts could not form. We find that UV mutagenesis does not produce these tyrosine tRNA ochre suppressor mutations. With lexA51 recA441 defective cells, the spontaneous yield of these mutations is elevated and UV irradiation produces a significant decrease in the numbers of this particular mutation. As explanation we suggest that the spontaneous appearance of these mutations reflects mutation at apurinic sites, the efficiency of which is elevated in lexA51 recA441 cells (with derepressed SOS functions and an activated form of RecA protein). The addition of UV damage in the DNA of these cells cannot further stimulate the positive functions that are required for the production of these mutations and are typically associated with UV mutagenesis (induction of SOS functions, activation of RecA protein and introduction of a targeting photoproduct) but apparently can have a negative effect on mutagenesis, hitherto not realized.This publication has 31 references indexed in Scilit:
- Specificity of mutagenesis resulting from the induction of the SOS system in the absence of mutagenic treatmentCell, 1984
- Changes in DNA base sequence induced by targeted mutagenesis of lambda phage by ultraviolet lightJournal of Molecular Biology, 1984
- Carcinogens induce targeted mutations in Escherichia coliCell, 1982
- Mutagenesis resulting from depurination is an SOS processMutation Research, 1982
- Influence of RecA protein on induced mutagenesisBiochimie, 1982
- Crowding depression of UV-mutagenesis in E. coliMutation Research, 1980
- Molecular basis of base substitution hotspots in Escherichia coliNature, 1978
- Persistence of pyrimidine dimers during post-replication repair in ultraviolet light-irradiated Escherichia coli K12Journal of Molecular Biology, 1974
- The role of nutrient broth supplementation in UV mutagenesis of E. coliMutation Research, 1973
- A determination of mutagen specificity in bacteria using nonsense mutants of bacteriophage T4Journal of Molecular Biology, 1967