Enhancement of UV survival, UV- and MMS-mutability, precise excision of Tn10 and complementation of umuC by plasmids of different incompatibility groups

Brunner, David P.; Traxler, Beth; Holt, Scott M.; Crose, Lori L.

doi:10.1016/0167-8817(86)90038-6

Cited by 19 publications

(8 citation statements)

References 31 publications

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“…Finally, it should be noted that the high level of mutagenesis promoted by the cloned rumAB (R391) operon is in stark contrast to the limited ability of the native R391 plasmid to promote mutagenesis functions (8,27,28,39,53). One obvious explanation for this difference is that the UV sensitization gene(s) carried by R391 (and other IncJ plasmids) (35,39,53) masks the inherent ability of rumAB (R391) to exhibit mutagenic DNA repair.…”

Section: Discussionmentioning

confidence: 60%

“…These so-called mutagenesis proteins can be expressed chromosomally, like the UmuDC proteins from Escherichia coli and Salmonella typhimurium (19,37,48,52), or episomally from certain naturally occurring plasmids (23,31,37,38). Indeed, R plasmids from over 10 different incompatibility groups can restore or increase the mutation frequency in a variety of E. coli strains, suggesting that they carry functionally active Umu homologs (8,27,28,39,53).…”

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confidence: 99%

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Characterization of the umu-complementing operon from R391

et al. 1995

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In addition to conferring resistances to antibiotics and heavy metals, certain R factors carry genes involved in mutagenic DNA repair. These plasmid-encoded genes are structurally and functionally related to the chromosomally encoded umuDC genes of Escherichia coli and Salmonella typhimurium. Three such plasmid operons, mucAB, impCAB, and samAB, have been characterized at the molecular level. Recently, we have identified three additional umu-complementing operons from IncJ plasmid R391 and IncL/M plasmids R446b and R471a. We report here the molecular characterization of the R391 umu-complementing operon. The nucleotide sequence of the minimal R plasmid umu-complementing (rum) region revealed an operon of two genes, rumA (R391) and rumB (R391) , with an upstream regulatory signal strongly resembling LexA-binding sites. Phylogenetic analysis revealed that the RumAB (R391) proteins are approximately equally diverged in sequence from the chromosomal UmuDC proteins and the other plasmid-encoded Umu-like proteins and represent a new subfamily. Genetic characterization of the rumAB (R391) operon revealed that in recA ؉ and recA1730 backgrounds, the rumAB (R391) operon was phenotypically indistinguishable from mucAB. In contrast, however, the rumAB (R391) operon gave levels of mutagenesis that were intermediate between those given by mucAB and umuDC in a recA430 strain. The latter phenotype was shown to correlate with the reduced posttranslational processing of the RumA (R391) protein to its mutagenically active form, RumA (R391) . Thus, the rumAB (R391) operon appears to possess characteristics that are reminiscent of both chromosome and plasmid-encoded umu-like operons.

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Section: Discussionmentioning

confidence: 60%

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confidence: 99%

Characterization of the umu-complementing operon from R391

et al. 1995

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“…Even though it appeared that the recombination reduction ability and the UV-sensitising functions were related, they were demonstrated to be separate functions by cloning [19,21]. In addition to the unusual UV-sensitising function, like many mobile elements [28] CTnR391, CTnR997 and CTnpMERPH have been shown to encode a UV-protection and mutagenesis-enhancing function [16]. In the case of CTnR391 this function is associated with the presence of two genes, rumA and rumB, which encode functional homologues of the E. coli UmuDC mutagenesis-enhancing proteins [21] and the well-studied MucAB system associated with pKM101 used in the Ames mutagen tester strains [29].…”

Section: Dna Repair Functionsmentioning

confidence: 95%

“…The only other report of an IncJ element was pMERPH from Pseudomonas putrefaciens isolated from the River Mersey, Great Britain, and transferred to Escherichia coli [14] (table 1). Transfer of IncJ elements has been demonstrated to a number of enterobacterial species including Escherichia coli K12, Salmonella typhimurium, Serratia marcessens, Proteus mirabilis 5006, Vibrio cholera (ElTor) and Pseudomonas [3, 5, [15][16][17]. The South African IncJ elements have been shown to be repressed for pilus synthesis, while in E. coli, CTnR997 has been shown to synthesise conjugative pili constitutively [15,18], possibly accounting for its higher transfer frequency.…”

Section: Introductionmentioning

confidence: 98%

The role of conjugative transposons in the Enterobacteriaceae

Pembroke

MacMahon

McGrath

2002

Cellular and Molecular Life Sciences (CMLS)

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Although widely studied in gram-positive Streptococci and in the gram-negative Bacteroides, there is a scarcity of information on the occurrence and nature of conjugative transposon-like elements in the well-studied Enterobacteriaceae. In fact, some of the major reviews on conjugative transposons prior to 1996 failed to mention their occurrence in this group. Recently, their presence has been reported in Salmonella, Vibrio and Proteus species, and in some cases such as the SXT element in Vibrio and the IncJ group element CTnR391, there has been some molecular characterization. The elements thus far examined appear to be larger than the common gram-positive conjugative transposons and to be mosaic in structure, with genes derived from several sources. Recent evidence suggests that in the Enterobacteriaceae the elements may be related to enteric pathogenicity islands. The evolution, distribution and role of these elements in the Enterobacteriaceae is discussed.

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“…First, research by others had suggested that they might contain umu analogs (5,39,54); second, unlike the IncN plasmid R46, which encodes mucAB; the IncI plasmid TP110, which encodes imppCAB, and the cryptic pSLT plasmid encoding samAB (all of which were isolated from Salmonella strains [23,30,38]), R391, R446b, and R471a were originally isolated from Providencia rettgeri (10, 36a), Morganella morganii (16, 36a), and Serratia marcescens (17), respectively, and therefore might have evolved differently from the previously identified Salmonella plasmids; and third, they appeared to promote mutagenesis functions to various degrees. In general, previous reports have suggested that R446b is more efficient at promoting mutagenesis functions than R471a (yet both come from the same plasmid incompatibility group) and both are much better than R391 (5,28,54). We hypothesized that if we were successful in cloning the umu-like genes from these plasmids, our results might provide us with a better insight into the structure-function relationship between these and the previously identified mutagenesis proteins.…”

Section: Discussionmentioning

confidence: 99%