The isolation and characterization of an X-ray-sensitive ultraviolet-resistant mutant of Escherichia coli

Glickman, Barry W.; Zwenk, H.; Sluis, C.A. van; Rörsch, A.

doi:10.1016/0005-2787(71)90121-3

Cited by 27 publications

(8 citation statements)

References 22 publications

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“…UV irradiation was carried out as described (22), and mutational spectra were prepared from 10-15 independent cultures grown to 4-6 X 108 cells per ml. lad mutants were selected by plating 10 p1 of the irradiated cell suspension in 3 ml ofsoft agar on plates containing phenyl-,D-igalactoside.…”

Section: Methodsmentioning

confidence: 99%

Mutational specificity of UV light in Escherichia coli: indications for a role of DNA secondary structure.

Todd¹,

Glickman²

1982

Proc. Natl. Acad. Sci. U.S.A.

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We used the lad forward mutagenesis system to determine the mutational specificity of UV-induced mutation in a repair-proficient (Uvr') and a repair-deficient (AUvrB) strain ofEscherichia coli. The spectra recovered at similar levels of mutagenesis were similar, the exception being a mutational hotspot at site A24 specific to the AUvrB strain. Mutations induced at this hotspot, as well as those induced at other mutational hotspots that were found to be common to both the Uvr' and Uvr-strains, involve G-C -* APT transitions. All of the hotspots are at sites of potential dipyrimidine photoproducts, such as thymine-cytosine and cytosine-cytosine dimers, or of pyrimidine-cytosine photoproduct Py-C* lesions. Each of these hotspots occurs at a site in the potential hairpin loop of quasi-palindromic sequences. These observations suggest an important role for DNA structure in determining the fate of UV-induced premutational lesions.The lacI system of E. coli provides a method for determining UV-induced mutational specificity at a large number of sites (1-3). In contrast, earlier studies in other systems generally relied upon the analysis ofreversion at a rather limited number of sites (4-6). Often the mutants analyzed in such reversion studies were originally induced by the mutagen (7); therefore, the possibility existed that preferentially mutable sites or hotspots had been selected and that these might behave atypically. Alternatively, the original mutation might have removed a critical DNA target sequence rendering the site practically immutable. Moreover, in studies of the reversion of nonsense mutations, the majority of "revertants" often occur not in the structural gene but at suppressor loci, which behave differently in their responses to UV light (4, 8, 9). The lacl system allows an examination of forward mutagenesis at 65 individual sites where nonsense mutations can arise by a single base substitution. Because both the DNA sequence and the location of the nonsense mutations have been established (10), each mutation can be attributed to a specific transition or transversion event.Detailed knowledge ofthe sites at which mutagenesis occurs and of the specific base changes produced may yield important clues about the premutagenic lesions and how they are processed. In the case ofUV irradiation, the mutational mechanism is poorly understood. Photoreactivation experiments suggest that mutagenesis in both excision-proficient and excision-deficient strains requires pyrimidine dimers (11,12). Nevertheless, considerable evidence exists that not all UV-induced mutagenesis occurs at the sites of induced lesions (13). For example, undamaged bacteriophage A plated on UV-irradiated hosts show high levels of recA+-dependent mutagenesis ("indirect mutagenesis") (14). In a current model, UV-induced mutagenesis in E. coli proceeds through a recA+-dependent, inducible error-prone repair pathway called "SOS" repair [reviewed by Witkin (13)]. It is postulated that, where alternative repair pathways are unable to function...

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Section: Methodsmentioning

confidence: 99%

Mutational specificity of UV light in Escherichia coli: indications for a role of DNA secondary structure.

Todd¹,

Glickman²

1982

Proc. Natl. Acad. Sci. U.S.A.

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“…Mutants were isolated by screening chemically mutagenized cells for the inability to act as the Frecipient in an Hfr cross and ensuring that F' transfer was not affected (93). recB was also independently isolated as a partially defective mutant (rorA) which displayed X-ray but not UV sensitivity (198,199). The mutations defined two complementation groups at 61 min on theE.…”

Section: Biological Functionsmentioning

confidence: 99%

“…recC is transcribed independently, although in the same orientation (178,540). Regulation of these genes is not affected by 199 a See text for more complete descriptions. Adapted from references 10, 233, and 577.…”

Section: Biological Functionsmentioning

confidence: 99%

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Biochemistry of homologous recombination in Escherichia coli.

Kowalczykowski¹,

Dixon²,

Eggleston³

et al. 1994

Microbiological Reviews

688

470

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“…MATERIALS AND METHODS The composition of media, the determination of cellular survival after X-ray and UV irradiation, and the measurement of DNA degradation have been described previously (5). In Table 1 the genotypes of the strains employed are listed.…”

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confidence: 99%

Comparison of the resA1 and polA1 Mutations in Isogenic Strains of Escherichia coli K-12

et al. 1973

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Strains carrying either the polAl or resAl mutation are deficient in DNA polymerase I, and the polAl and resAl mutations do not complement in merozygotes. The effect of these mutations in otherwise identical genetic backgrounds was studied: after ultraviolet irradiation both strains degrade their DNA more rapidly and more extensively than the wild-type strains. However, after X-ray irradiation the resAl strain shows little DNA breakdown and repairs its single-strand breaks. In contrast, the polAl strain degrades its DNA extensively, and single-strand breaks are not repaired. Moreover, the resAl strain is capable of supporting the growth of a red-bacteriophage lambda, whereas the polAl strain is not.

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The isolation and characterization of an X-ray-sensitive ultraviolet-resistant mutant of Escherichia coli

Cited by 27 publications

References 22 publications

Mutational specificity of UV light in Escherichia coli: indications for a role of DNA secondary structure.

Mutational specificity of UV light in Escherichia coli: indications for a role of DNA secondary structure.

Biochemistry of homologous recombination in Escherichia coli.

Comparison of the resA1 and polA1 Mutations in Isogenic Strains of Escherichia coli K-12

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