Chromosome and Low Copy Plasmid Segregation in E. coli: Visual Evidence for Distinct Mechanisms

Gordon, G. Scott; Sitnikov, Dmitry; Webb, Chris; Teleman, Aurelio A.; Straight, Aaron F.; Losick, Richard; Murray, Andrew W.; Wright, Andrew

doi:10.1016/s0092-8674(00)80377-3

Cited by 371 publications

(457 citation statements)

References 43 publications

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“…The events involved in chromosome segregation and partitioning include resolution of chromosome dimers resulting from recombinational crossovers between sister chromosomes, decatenation of interlinked daughter chromosomes, and movement of daughter chromosomes away from each other (43). Recent evidence suggests that bacterial chromosome segregation is an active mitosis-like process and that the origin of replication (oriC) of the E. coli and B. subtilis chromosome has a specific orientation during the cell cycle (9,10,20,44). Thus, in newborn cells oriC is oriented toward a cell pole; after replication of this region, one of the two origins moves rapidly toward the opposite pole of the cell while the termination region remains centrally located (10,44).…”

Section: Discussionmentioning

confidence: 99%

Penicillin-Binding Protein-Related Factor A Is Required for Proper Chromosome Segregation in Bacillus subtilis

Pedersen

Setlow

2000

J Bacteriol

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Previous work has shown that the ponA gene, encoding penicillin-binding protein 1 (PBP1), is in a two-gene operon with prfA (PBP-related factor A) (also called recU), which encodes a putative 206-residue basic protein (pI ‫؍‬ 10.1) with no significant sequence homology to proteins with known functions. Inactivation of prfA results in cells that grow slower and vary significantly in length relative to wild-type cells. We now show that prfA mutant cells have a defect in chromosome segregation resulting in the production of ϳ0.9 to 3% anucleate cells in prfA cultures grown at 30 or 37°C in rich medium and that the lack of PrfA exacerbates the chromosome segregation defect in smc and spoOJ mutant cells. In addition, overexpression of prfA was found to be toxic for and cause nucleoid condensation in Escherichia coli.Penicillin-binding proteins (PBPs), which catalyze the polymerization and cross-linking of bacterial peptidoglycan, can be divided into three classes based on their amino acid sequence: the low-molecular-weight PBPs and the high-molecular-weight (HMW) class A and class B PBPs (8). The HMW class B PBPs are monofunctional transpeptidases, some of which have essential functions in septation and maintenance of cell shape (8), while the HMW class A PBPs have both transglycosylase and transpeptidase activities (14, 42) and appear to be somewhat functionally redundant (17, 34). The Bacillus subtilis ponA gene, coding for the HMW class A PBP1, is transcribed predominantly during log-phase growth (34). Previous work with B. subtilis mutants lacking one or several of the three known HMW class A PBPs (PBP1, PBP2c, and PBP4) showed that (i) lack of PBP1 results in slower growth, increased cell length, and decreased cell diameter and (ii) PBP1 is functionally more important than PBP2c and PBP4 (34). It was also recently demonstrated that PBP1 localizes to cell division sites and plays an important role in the formation of the peptidoglycan division septum in vegetative cells of B. subtilis (30).The ponA gene is part of a two-gene operon that also includes prfA (PBP-related factor A [note that in the B. subtilis genome database, prfA is called recU]), which is located immediately upstream of and cotranscribed with ponA (33). prfA codes for a putative 206 residue, basic protein (pI of 10.1), which has no significant sequence homology to proteins with known functions. However, DNA sequencing has indicated that genes encoding similar proteins are present in a large number of gram-positive bacteria: a BLAST search (2) of prfA against completed and unfinished microbial genomes (preliminary sequence data were obtained from The Institute of Genomic Research Website at http://www.tigr.org) produced sequences with significant homology from 10 different grampositive organisms, while no prfA homologs were detected in gram-negative bacteria by this analysis. The former organisms include Enterococcus faecalis (54% identity in a 192-aminoacid overlap), Staphylococcus aureus (58% identity in a 167-amino-acid overlap), Streptococcus p...

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Section: Discussionmentioning

confidence: 99%

Penicillin-Binding Protein-Related Factor A Is Required for Proper Chromosome Segregation in Bacillus subtilis

Pedersen

Setlow

2000

J Bacteriol

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“…Today, techniques such as fluorescent repressor operator systems 6 and the ParB-GFP fusions parS sequences 7 allow visualization of the location in the cell of specific chromosomal loci to investigate chromosome positioning and dynamics.…”

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confidence: 99%

Short-time movement of E. coli chromosomal loci depends on coordinate and subcellular localization

et al. 2013

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In bacteria, chromosomal architecture shows strong spatial and temporal organization, and regulates key cellular functions, such as transcription. Tracking the motion of chromosomal loci at short timescales provides information related to both the physical state of the nucleo-protein complex and its local environment, independent of large-scale motions related to genome segregation. Here we investigate the short-time (0.1-10 s) dynamics of fluorescently labelled chromosomal loci in Escherichia coli at different growth rates. At these timescales, we observe for the first time a dependence of the loci's apparent diffusion on both their subcellular localization and chromosomal coordinate, and we provide evidence that the properties of the chromosome are similar in the tested growth conditions. Our results indicate that either non-equilibrium fluctuations due to enzyme activity or the organization of the genome as a polymer-protein complex vary as a function of the distance from the origin of replication.

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“…Although proteins, sites, and mechanisms involved in physical separation (decatenation) of bacterial chromosomes have been characterized, much less is known about the mechanisms governing efficient partitioning to daughter cells (for review, see Hiraga 1992;Wake and Errington 1995). Recent work has shown that the chromosomal region around the origin of replication (oriC) is in a defined orientation for most of the bacterial (B. subtilis and E. coli) cell cycle and that newly replicated oriC regions are rapidly separated from each other (Glaser et al 1997;Gordon et al 1997;Lin et al 1997;Webb et al 1997). The origin regions are found toward the poles of the highly condensed nucleoid body, oriented toward the ends of the cell.…”

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confidence: 99%

“…The origin regions are found toward the poles of the highly condensed nucleoid body, oriented toward the ends of the cell. The rapid separation and localization of oriC regions indicate the function of a mitotic-like apparatus in prokaryotes (Glaser et al 1997;Gordon et al 1997;Lin et al 1997;Webb et al 1997).…”

mentioning

confidence: 99%

Characterization of a prokaryotic SMC protein involved in chromosome partitioning

Britton

Lin²,

Grossman³

1998

Genes & Development

263

298

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smc of Bacillus subtilis encodes a homolog of eukaryotic SMC proteins involved in chromosome condensation, pairing, and partitioning. A null mutation in B. subtilis smc caused a temperature-sensitive-lethal phenotype in rich medium. Under permissive conditions, the mutant had abnormal nucleoids, ∼10% of the cells were anucleate, and assembly of foci of the chromosome partitioning protein Spo0J was altered. In combination with a null mutation in spo0J, the smc mutation caused a synthetic phenotype; cell growth was slower and ∼25% of the cells were anucleate. Our results demonstrate that the B. subtilis Smc protein, like its eukaryotic counterpart, plays an important role in chromosome structure and partitioning.

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Chromosome and Low Copy Plasmid Segregation in E. coli: Visual Evidence for Distinct Mechanisms

Cited by 371 publications

References 43 publications

Penicillin-Binding Protein-Related Factor A Is Required for Proper Chromosome Segregation in Bacillus subtilis

Penicillin-Binding Protein-Related Factor A Is Required for Proper Chromosome Segregation in Bacillus subtilis

Short-time movement of E. coli chromosomal loci depends on coordinate and subcellular localization

Characterization of a prokaryotic SMC protein involved in chromosome partitioning

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