Role of RepA and DnaA Proteins in the Opening of the Origin of DNA Replication of an IncB Plasmid

Betteridge, Thu; Yang, Jiyeon; Pittard, A. J.; Praszkier, Judyta

doi:10.1128/jb.186.12.3785-3793.2004

Cited by 14 publications

(9 citation statements)

References 58 publications

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“…For many bacterial plasmids, plasmid replication requires the combined actions of chromosome-encoded DnaA protein and a plasmid-encoded initiator protein (Rep protein), expression of which determines the frequency of replication initiation (Betteridge et al, 2004). Fig.…”

Section: Discussionmentioning

confidence: 99%

A new tubRZ operon involved in the maintenance of the Bacillus sphaericus mosquitocidal plasmid pBsph

Zhao

et al. 2014

Microbiology

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A new tubRZ operon involved in the maintenance of the Bacillus sphaericus mosquitocidal plasmid pBsph pBsph is a mosquitocidal plasmid first identified from Bacillus sphaericus, encoding binary toxins (Bin toxins) that are highly toxic to mosquito larvae. This plasmid plays an important role in the maintenance and evolution of the bin genes in B. sphaericus. However, little is known about its replication and partitioning. Here, we identified a 2.4 kb minimal replicon of pBsph plasmid that contained an operon encoding TubR-Bs and TubZ-Bs, each of which was shown to be required for plasmid replication. TubR-Bs was shown to be a transcriptional repressor of tubRZ-Bs genes and could bind cooperatively to the replication origin of eleven 12 bp degenerate repeats in three blocks, and this binding was essential for plasmid replication. TubZ-Bs exhibited GTPase activities and interacted with TubR-Bs : DNA complex to form a ternary nucleoprotein apparatus. Electron and fluorescence microscopy revealed that TubZ-Bs assembled filaments both in vitro and in vivo, and two point mutations in TubZ-Bs (T114A and Y260A) that severely impaired the GTPase and polymerization activities were found to be defective for plasmid maintenance. Further investigation demonstrated that overproduction of TubZ-Bs-GFP or its mutant forms significantly reduced the stability of pBsph. Taken together, these results suggested that TubR-Bs and TubZBs are involved in the replication and probably in the partitioning of pBsph plasmid, increasing our understanding of the genetic particularity of TubZ systems.

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Section: Discussionmentioning

confidence: 99%

A new tubRZ operon involved in the maintenance of the Bacillus sphaericus mosquitocidal plasmid pBsph

Zhao

et al. 2014

Microbiology

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“…These plasmids contain at least one DnaA box in their oriV sequences [38-43]. For other plasmids, DnaA participates only as an accessory, but these plasmids also contain DnaA boxes in their origins of replication (e.g., pR1) [44].…”

Section: Discussionmentioning

confidence: 99%

The replication origin of a repABC plasmid

et al. 2011

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BackgroundrepABC operons are present on large, low copy-number plasmids and on some secondary chromosomes in at least 19 α-proteobacterial genera, and are responsible for the replication and segregation properties of these replicons. These operons consist, with some variations, of three genes: repA, repB, and repC. RepA and RepB are involved in plasmid partitioning and in the negative regulation of their own transcription, and RepC is the limiting factor for replication. An antisense RNA encoded between the repB-repC genes modulates repC expression.ResultsTo identify the minimal region of the Rhizobium etli p42d plasmid that is capable of autonomous replication, we amplified different regions of the repABC operon using PCR and cloned the regions into a suicide vector. The resulting vectors were then introduced into R. etli strains that did or did not contain p42d. The minimal replicon consisted of a repC open reading frame under the control of a constitutive promoter with a Shine-Dalgarno sequence that we designed. A sequence analysis of repC revealed the presence of a large A+T-rich region but no iterons or DnaA boxes. Silent mutations that modified the A+T content of this region eliminated the replication capability of the plasmid. The minimal replicon could not be introduced into R. etli strain containing p42d, but similar constructs that carried repC from Sinorhizobium meliloti pSymA or the linear chromosome of Agrobacterium tumefaciens replicated in the presence or absence of p42d, indicating that RepC is an incompatibility factor. A hybrid gene construct expressing a RepC protein with the first 362 amino acid residues from p42d RepC and the last 39 amino acid residues of RepC from SymA was able to replicate in the presence of p42d.ConclusionsRepC is the only element encoded in the repABC operon of the R. etli p42d plasmid that is necessary and sufficient for plasmid replication and is probably the initiator protein. The oriV of this plasmid resides within the repC gene and is located close to or inside of a large A+T region. RepC can act as an incompatibility factor, and the last 39 amino acid residues of the carboxy-terminal region of this protein are involved in promoting this phenotype.

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“…This weakly conserved repetitive and spacing-sensitive character of the ACR domain shares a similar architecture with the repeat region that is linked to the replication origin of, for instance, repABC-type plasmids. Like these origin-associated repeats, the ACR domain could play a similar role in DNA unwinding (Jakimowicz et al, 2002;Betteridge et al, 2004;this work). A candidate protein facilitating strand separation in Agrobacterium plasmids is virC1.…”

Section: Discussionmentioning

confidence: 99%

Plant-Derived Transfer DNAs

et al. 2005

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The transfer of DNA from Agrobacterium to plant cell nuclei is initiated by a cleavage reaction within the 25-bp right border of Ti plasmids. In an effort to develop all-native DNA transformation vectors, 50 putative right border alternatives were identified in both plant expressed sequence tags and genomic DNA. Efficacy tests in a tobacco (Nicotiana tabacum) model system demonstrated that 14 of these elements displayed at least 50% of the activity of conventional Agrobacterium transfer DNA borders. Four of the most effective plant-derived right border alternatives were found to be associated with intron-exon junctions. Additional elements were embedded within introns, exons, untranslated trailers, and intergenic DNA. Based on the identification of a single right border alternative in Arabidopsis and three in rice (Oryza sativa), the occurrence of this motif was estimated at a frequency of at least 0.8 3 10 28 . Modification of plasmid DNA sequences flanking the alternative borders demonstrated that both upstream and downstream sequences play an important role in initiating DNA transfer. Optimal DNA transfer required the elements to be preceded by pyrimidine residues interspaced by AC-rich trinucleotides. Alteration of this organization lowered transformation frequencies by 46% to 93%. Despite their weaker resemblance with left borders, right border alternatives also functioned effectively in terminating DNA transfer, if both associated with an upstream A[C/T

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Role of RepA and DnaA Proteins in the Opening of the Origin of DNA Replication of an IncB Plasmid

Cited by 14 publications

References 58 publications

A new tubRZ operon involved in the maintenance of the Bacillus sphaericus mosquitocidal plasmid pBsph

A new tubRZ operon involved in the maintenance of the Bacillus sphaericus mosquitocidal plasmid pBsph

The replication origin of a repABC plasmid

Plant-Derived Transfer DNAs

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