A Type Ib ParB Protein Involved in Plasmid Partitioning in a Gram-Positive Bacterium

Yin, Ping; Li, Taiyuan; Xie, Mengying; Jiang, Leiming; Zhang, Yi

doi:10.1128/jb.01232-06

Cited by 15 publications

(17 citation statements)

References 38 publications

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“…Significant homology is typical among the ParA proteins of different plasmid systems, but usually there is little, if any, similarity among ParB proteins. Most of the reported characterized systems have involved plasmids of gram-negative bacteria; however, similar functional systems among gram-positive bacteria have recently been identified (28,48,51). Clearly, the results from the present study are consistent with RepB and RepC corresponding to pAD1 ParA and ParB, respectively, and the iterons correspond to the "centromere" (parS).…”

Section: Discussionsupporting

confidence: 81%

“…The results reported here for pAD1, as well as two other recent reports (28,51), show that systems closely resembling those found in a number of gram-negative bacteria are also functional in at least some gram-positive organisms. The system of pAD1 characterized here represents the first among the widely disseminated enterococcal pheromone-responding plasmids.…”

Section: Discussionsupporting

confidence: 65%

“…However, efficient partitioning by ItA alone seems to rule out this possibility, as similar inverted repeats are absent in ItA. As no obvious effects of ParA homologues on the mobility shift and/or the DNase I protection patterns were observed in Type Ib par systems (with the exception of TP228 mentioned above), some mechanistic differences among them are possible (1,30,51).…”

Section: Discussionmentioning

confidence: 86%

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Characterization of an Active Partition System for theEnterococcus faecalisPheromone-Responding Plasmid pAD1

et al. 2007

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Enterococcus faecalis plasmid pAD1 is a 60-kb conjugative, low-copy-number plasmid that encodes a mating response to the peptide sex pheromone cAD1 and a cytolytic exotoxin that contributes to virulence. Although aspects of conjugation have been studied extensively, relatively little is known about the control of pAD1 maintenance. Previous work on pAD1 identified a 5-kb region of DNA sufficient to support replication, copy control, and stable inheritance (K. pAD1 is representative of a large and globally disseminated family of conjugative plasmids in Enterococcus faecalis. It is a 60-kb, low-copy-number (one to four copies per chromosome) element that encodes a mating response to the peptide sex pheromone cAD1. It also determines a virulence-related cytolytic (hemolysin/bacteriocin) exotoxin, as well as resistance to UV light. (For recent reviews of pheromone-responding plasmids, see references 6, 7, and 8.) Although aspects of conjugation have been studied extensively, much less is known about the control of pAD1 replication and maintenance. A previous investigation of pAD1 identified a 5-kb region of DNA able to support replication, copy control, and stable inheritance, and it was found that three determinants, designated repA, repB, and repC, were necessary for normal maintenance (46). Data suggested that RepA (336 amino acids) was involved in replication initiation whereas RepB (281 amino acids) and RepC (123 amino acids) were involved in maintaining copy number and stability. As illustrated in Fig. 1, the repA and repB determinants diverge and are separated by a series of iterons, whereas repC is immediately downstream of, and probably transcribed together with, repB. The iterons correspond to two groups of octanucleotide repeats with the sequence TAGTARRR: 13 iterons and 12 iterons are separated by a 75-bp AT-rich (80%) "spacer." There are also three tandemly arranged iterons located downstream of repC.ERecently, the pAD1 replication initiator (RepA) and the origin of vegetative replication (oriV) were identified and characterized (15). It was found that repA alone, under an artificial promoter, was sufficient for replication when cloned on a plasmid devoid of replication ability. The chimera maintained itself at a high copy number (20 to 30 copies per chromosome), in contrast to the low copy number of intact pAD1. In addition, the replication origin was found to be located within a 170-bp segment of repA, which alone could facilitate replication in cis as long as RepA was provided in trans. RepA was also found to bind specifically to several sites containing inverted-repeat sequences within oriV and bound nonspecifically to singlestranded DNA (15).Whereas RepA alone was able to support replication, the high-copy-number repA chimera was not highly stable in that after 30 generations of unselected growth in broth about 60% of the cells were observed to have lost the plasmid (15); an efficient partitioning system was clearly missing. Good candidates for components of a partition system in the intact pAD1 are...

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Section: Discussionsupporting

confidence: 81%

Section: Discussionsupporting

confidence: 65%

Section: Discussionmentioning

confidence: 86%

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Characterization of an Active Partition System for theEnterococcus faecalisPheromone-Responding Plasmid pAD1

et al. 2007

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“…Nevertheless, the majority of the type Ib centromere‐binding proteins characterized so far are of gram‐negative bacterial origin (Yin et al . ). Tsuchida et al .…”

Section: Discussionmentioning

confidence: 97%

pCGR2 copy number depends on the par locus that forms a ParC-ParB-DNA partition complex in Corynebacterium glutamicum

et al. 2013

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Aims: To characterize the par system of Corynebacterium glutamicum pCGR2 and to manipulate the par components to effectively manipulate plasmid copy number. Methods and Results: ParB binds sequence specifically to centromere-binding sites around the parAB operon and serves as an autorepressor. A small ORF (orf4, later named parC) downstream of parAB encodes a protein with 23Á7% sequence identity with ParB. ParB is also implicated in the repression of parC transcription. Nonetheless, this ParC protein does not bind to centromerebinding sites and is not essential for plasmid stability. Introduction of a frameshift mutation within ParC implicated the protein in regulation of both parAB and parC. Electrophoretic Mobility Shift Assay confirmed a previously unreported ParC-ParB-parS partition complex. ParC also interacts directly with ParB without the mediation of the centromere sites. Deletion of the par components resulted in different plasmid copy numbers. Conclusions: A previously unreported ParC-ParB-parS partition complex is formed in pCGR2, where interaction of ParC with ParB-parS may affect the level of repression by ParB. Modifying the par components and antisense RNA enables manipulation of plasmid copy number to varying degrees. Significance and Impact of Study: Genetically manipulating the par components, in combination with deactivation of antisense RNA, is a novel approach to artificially elevate plasmid copy number. This approach can be applied for development of new genetic engineering tools.

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“…The recessive 3′ end was labeled with [α‐ 32 P] dATP (Furui Biotech, Beijing, China) by Klenow fragment, and then subjected to the same binding reaction as in the gel retardation assay. DNase I footprinting was performed as previously described [14]. The ladders were produced using the Sanger dideoxy method and Ta20 primer that was end‐labeled by T4 polynucleotide kinase and [γ‐ 32 P] ATP.…”

Section: Methodsmentioning

confidence: 99%

A novel toxin–antitoxin operon talA/B from the Gram‐positive bacterium Leifsonia xyli subsp. cynodontis

et al. 2008

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Here we report a toxin-antitoxin (TA) operon talAB identified from the Gram-positive bacterium Leifsonia xyli subsp. cynodontis. It is shown that talB encodes a broad-host cytotoxin functioning in different Gram-positive bacteria, while talA encodes its antidote. TalA and TalB form different hetero-oligomers in vitro; these hetero-oligomers, but not the antitoxin TalA, strongly bind to the talAB promoter region containing two inverted repeats. This represents a new mechanism of binding the promoter of a TA operon by the toxin and antitoxin complexes.

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A Type Ib ParB Protein Involved in Plasmid Partitioning in a Gram-Positive Bacterium

Cited by 15 publications

References 38 publications

Characterization of an Active Partition System for theEnterococcus faecalisPheromone-Responding Plasmid pAD1

Characterization of an Active Partition System for theEnterococcus faecalisPheromone-Responding Plasmid pAD1

pCGR2 copy number depends on the par locus that forms a ParC-ParB-DNA partition complex in Corynebacterium glutamicum

A novel toxin–antitoxin operon talA/B from the Gram‐positive bacterium Leifsonia xyli subsp. cynodontis

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