Mutagenic DNA repair in Escherichia coli XVII. Effect of temperature-sensitive DnaE proteins on the induction of streptomycin-resistant mutations by UV light

Mutagenesis ◽  
1990 ◽  
Vol 5 (1) ◽  
pp. 31-34 ◽  
Author(s):  
Firdaus Sharif ◽  
Bryn A. Bridges
Keyword(s):  
Escherichia Coli ◽  
Dna Repair ◽  
Uv Light ◽  
Effect Of Temperature ◽  
Temperature Sensitive ◽  
Mutagenic Dna Repair

scholarly journals Incubation at the nonpermissive temperature induces deficiencies in UV resistance and mutagenesis in mouse mutant cells expressing a temperature-sensitive ubiquitin-activating enzyme (E1).

1997 ◽  
Vol 17 (3) ◽  
pp. 1484-1489 ◽  
Author(s):  
H Ikehata ◽  
S Kaneda ◽  
F Yamao ◽  
T Seno ◽  
T Ono ◽  
...  
Keyword(s):  
Dna Repair ◽  
Mammalian Cells ◽  
Uv Light ◽  
Temperature Sensitive ◽  
Restrictive Temperature ◽  
Nonpermissive Temperature ◽  
Conjugation System ◽  
Ubiquitin Conjugating Enzyme ◽  
Mutant Phenotypes ◽  
Mutant Cells

In temperature-sensitive (ts) mutants of mouse FM3A cells, the levels of mutagenesis and survival of cells treated with DNA-damaging agents have been difficult to assess because they are killed after their mutant phenotypes are expressed at the nonpermissive temperature. To avoid this difficulty, we incubated the ts mutant cells at the restrictive temperature, 39 degrees C, for only a limited period after inducing DNA damage. We used ts mutants defective in genes for ubiquitin-activating enzyme (E1), DNA polymerase alpha, and p34(cdc2) kinase. Whereas the latter two showed no effect, E1 mutants were sensitized remarkably to UV light if incubated at 39 degrees C for limited periods after UV exposure. Eighty-five percent of the sensitization occurred within the first 12 h of incubation at 39 degrees C, and more than 36 h at 39 degrees C did not produce any further sensitization. Moreover, while the 39 degrees C incubation gave E1 mutants a moderate spontaneous mutator phenotype, the same treatment significantly diminished the level of UV-induced 6-thioguanine resistance mutagenesis and extended the time necessary for expression of the mutation phenotype. These characteristics of E1 mutants are reminiscent of the defective DNA repair phenotypes of Saccharomyces cerevisiae rad6 mutants, which have defects in a ubiquitin-conjugating enzyme (E2), to which E1 is known to transfer ubiquitin. These results demonstrate the involvement of E1 in eukaryotic DNA repair and mutagenesis and provide the first direct evidence that the ubiquitin-conjugation system contributes to DNA repair in mammalian cells.

Mutagenic DNA repair in Escherichia coli

1975 ◽  
Vol 140 (3) ◽  
pp. 221-230 ◽  
Author(s):  
O. P. Doubleday ◽  
B. A. Bridges ◽  
M. H. L. Green
Keyword(s):  
Escherichia Coli ◽  
Dna Repair ◽  
Mutagenic Dna Repair
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