Expression of the plasmid pKM101-determined DNA repair system in recA − and lex − strains of Escherichia coli

Monti‐Bragadin, C.; Babudri, Nora; Samer, L.

doi:10.1007/bf00325827

Cited by 65 publications

(18 citation statements)

References 13 publications

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“…No survivalor mutation-enhancing effect of mucAB after UV irradiation was seen in the RecA-mutant of E. coli WP100 (recA56), as already reported for the original R factor plasmids in Rec-S. typhimurium (25) and RecA-E. coli (32,54,55).…”

Section: Methodssupporting

confidence: 71%

“…The noninducible nature of the lexA3 mutant is due to the inability of the mutant LexA repressor to be cleaved upon mutagenic treatment and therefore to the absence of the capacity to derepress SOSregulated genes (17). The effect of mucAB on noninducible E. coli has been examined with positive (32,55) and negative (39) results. We think that this discrepancy was due to instability of the large plasmid, because we observed fragmentation of the 35.4-kb pKM101 in the lexA3 host in parallel with loss of mucAB activity (data not shown).…”

Section: Discussionmentioning

confidence: 99%

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Heterospecific expression of misrepair-enhancing activity of mucAB in Escherichia coli and Bacillus subtilis

Tazaki¹,

Tanaka²,

Shinozaki³

1991

J Bacteriol

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Enterobacterial plasmid genes mucAB, which possess error-prone repair activity, were cloned and sequenced independently of a sequence previously determined (K.L. Perry, S.J. Elledge, B.B. Mitchell, L. Marsh, and G.C. Walker, Proc. Natl. Acad. Sci. USA 82:4331-4335, 1985). The survival- and mutation-enhancing activities of mucAB ligated to the MLSr promoter of a Bacillus subtilis plasmid in the shuttle vector pTE22R were expressed in B. subtilis as well as in Escherichia coli after mutagenic treatment. mucAB fragments with 5' deletions of various lengths up to the base sequence encoding Ala-26-Gly-27, the putative RecA-mediated cleavage site of the MucA protein, showed mutation-enhancing activity for noninducible lexA3 E. coli when ligated to the MLSr promoter in frame. This activity was lost by extending the deletion downstream. The formations of MucA and MucB proteins in B. subtilis and E. coli were demonstrated by Western blot (immunoblot) analysis. MucA cleavage in Rec+ B. subtilis was observed only after treatment with an alkylating agent and was not observed in RecA- and RecE- strains, whereas in E. coli cleavage was observed in Rec+ cells after treatment with either mitomycin C or an alkylating agent but was not detected in RecA- cells. Common activity of B. subtilis Rec and E. coli RecA in the induction of mutants is suggested.

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Section: Methodssupporting

confidence: 71%

Section: Discussionmentioning

confidence: 99%

Heterospecific expression of misrepair-enhancing activity of mucAB in Escherichia coli and Bacillus subtilis

Tazaki¹,

Tanaka²,

Shinozaki³

1991

J Bacteriol

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“…mucAB also restores inducible mutagenesis to normally nonmutable recA430 and lexA4(Ind-) strains of E. coli (6,7,29,31,57). In this report, we demonstrate that mucAB can also restore mutability to recA433 and recA435 strains.…”

mentioning

confidence: 99%

The enhanced mutagenic potential of the MucAB proteins correlates with the highly efficient processing of the MucA protein

et al. 1992

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Inducible mutagenesis in Escherichia coli requires the direct action of the chromosomally encoded UmuDC proteins or functional homologs found on certain naturally occurring plasmids. Although structurally similar, the five umu-like operons that have been characterized at the molecular level vary in their ability to enhance cellular and phage mutagenesis; of these operons, the mucAB genes from the N-group plasmid pKM101 are the most efficient at promoting mutagenesis. During the mutagenic process, UmuD is posttranslationally processed to an active form, UmuD'. To explain the more potent mutagenic efficiency of mucAB compared with that of umuDC it has been suggested that unlike UmuD, intact MucA is functional for mutagenesis. To examine this possibility, we have overproduced and purified the MucA protein. Although functionally similar to UmuD, MucA was cleaved much more rapidly both in vitro and in vivo than UmuD. In vivo, restoration of mutagenesis functions to normally nonmutable recA430, recA433, recA435, or recA730 A(umuDC)595::cat strains by either MucA+ or mutant MucA protein correlated with the appearance of the cleavage product, MucA'. These results suggest that most of the differences in mutagenic phenotype exhibited by MucAB and UmuDC correlate with the efficiency of posttranslational processing of MucA and UmuD rather than an inherent activity of the unprocessed proteins.

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“…In Escherichia coli, thermally-induced expression of the tif-I mutation similarly causes enhancement of spontaneous and u.v.-induced mutagenesis (Witkin, I 974). The effects of both plasmid expression (MacPhee, 1973 ;Monti-Bragadin, Babudri & Samer, 1976) and tif-I expression (Castellazzi, George & Buttin, 1972) are r e d + dependent. In addition novel DNA synthesis characteristics are found in the presence of plasmids (MacPhee, 1974;Wilkins, 1975) and when t$r is expressed (Radman et al, 1976).…”

mentioning

confidence: 99%

Spontaneous and Ultraviolet-induced Mutation in Escherichia coli: Interaction Between Plasmid and tif-1 Mutator Effects

Doubleday¹,

Green²,

Bridges³

1977

Journal of General Microbiology

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I N T R O D U C T I O NCertain plasmids increase ultraviolet (u.v.) resistance and spontaneous and u .v. mutagenesis in Salmonella typhimurium (Howarth, I 966; MacPhee, 1973 ;Mortelmans & Stocker, 1976). In Escherichia coli, thermally-induced expression of the tif-I mutation similarly causes enhancement of spontaneous and u.v.-induced mutagenesis (Witkin, I 974). The effects of both plasmid expression (MacPhee, 1973 ;Monti-Bragadin, Babudri & Samer, 1976) and tif-I expression (Castellazzi, George & Buttin, 1972) are r e d + dependent. In addition novel DNA synthesis characteristics are found in the presence of plasmids (MacPhee, 1974;Wilkins, 1975) and when t$r is expressed (Radman et al., 1976). These common features prompted us to examine the interaction between the plasmid and tif-1 effects in an attempt to decide whether or not they act through the same mechanism. METHODS Plasmid ~K M I O Iwas transferred from Salmonetla typhimurium TAIOO (McCann et al., 1975) into Escherichia coli W P~ uvvA trp (Hill, 1965) and its non-filamenting t$I sf; derivative WP&NF (Witkin, 1976) using ampicillin selection. Details of the mutation system of m 2 and its derivatives and general methods have been published elsewhere (Bridges et al., 1973). Selective plates for Trp' revertants contained Difco Casamino acids (0.4%, w/v). tryptophan (0.125pg ml-l) and adenine (75 pg ml-l), which has been shown to potentiate tif-1 mutability (Witkin I 974). Bacterial viability was determined by plating appropriate dilutions on the same medium.Exponentially growing cultures were obtained by diluting an overnight broth culture I :IOO into fresh nutrient broth and incubating at 32 "C. and their parental strains at 44 "C for several hours did not result in lethality. However, ~~9 0 1 , unlike the other strains, filamented at this temperature. This was attributed to the presence of the ~K M I O I plasmid, since acridine orange curing of ~~9 0 1 resulted in reversion to the non-filamenting properties of WP44sNF.In Fig. I, spontaneous mutation is plotted as a function of the period of incubation of plates at 44 "C. Strain W'p2 uvrA was unaffected by this treatment (data not shown). Strains W P~~~N Fand cMgo I showed thermal enhancement of spontaneous mutability, although incubation of ~~9 0 1 for longer than 2 h resulted in a reduction in the number of additional mutants. This loss was presumed to relate to the plasmid, since spontaneous mutability of ~~8 9 1 was decreased by incubation at 44 "C ( Fig. I

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Expression of the plasmid pKM101-determined DNA repair system in recA − and lex − strains of Escherichia coli

Cited by 65 publications

References 13 publications

Heterospecific expression of misrepair-enhancing activity of mucAB in Escherichia coli and Bacillus subtilis

Heterospecific expression of misrepair-enhancing activity of mucAB in Escherichia coli and Bacillus subtilis

The enhanced mutagenic potential of the MucAB proteins correlates with the highly efficient processing of the MucA protein

Spontaneous and Ultraviolet-induced Mutation in Escherichia coli: Interaction Between Plasmid and tif-1 Mutator Effects

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