Generation of buds, swellings, and branches instead of filaments after blocking the cell cycle of Rhizobium meliloti

Latch, Judith N.; Margolin, William

doi:10.1128/jb.179.7.2373-2381.1997

Cited by 75 publications

(74 citation statements)

References 36 publications

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“…Our results concerning the expression of ftsZ Cg under Plac are in partial agreement with the results obtained in Rhizobium (Sinorhizobium) meliloti (another rod-shaped bacterium that lacks MreB homologues) (Latch & Margolin, 1997) and Mycobacterium tuberculosis (Dziadek et al, 2002). It may be concluded that in rod-shaped micro-organisms lacking MreB, branching and swelling are default pathways for increasing mass when cell division is blocked either by FtsZ overproduction (Latch & Margolin, 1997) or by partial depletion of FtsZ (this work).…”

Section: Discussionsupporting

confidence: 81%

“…It may be concluded that in rod-shaped micro-organisms lacking MreB, branching and swelling are default pathways for increasing mass when cell division is blocked either by FtsZ overproduction (Latch & Margolin, 1997) or by partial depletion of FtsZ (this work). Daniel & Errington (2003) used fluorescent vancomycin to determine the spatial pattern of peptidoglycan biosynthesis in C. glutamicum, and observed that cell division septa and cell poles were labelled by vancomycin.…”

Section: Discussionmentioning

confidence: 99%

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Altered morphology produced by ftsZ expression in Corynebacterium glutamicum ATCC 13869

et al. 2005

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Corynebacterium glutamicum is a Gram-positive bacterium that lacks the cell division FtsA protein and actin-like MreB proteins responsible for determining cylindrical cell shape. When the cell division ftsZ gene from C. glutamicum (ftsZ Cg ) was cloned in different multicopy plasmids, the resulting constructions could not be introduced into C. glutamicum; it was assumed that elevated levels of FtsZ Cg result in lethality. The presence of a truncated ftsZ Cg and a complete ftsZ Cg under the control of Plac led to a fourfold reduction in the intracellular levels of FtsZ, generating aberrant cells displaying buds, branches and knots, but no filaments. A 20-fold reduction of the FtsZ level by transformation with a plasmid carrying the Escherichia coli lacI gene dramatically reduced the growth rate of C. glutamicum, and the cells were larger and club-shaped. Immunofluorescence microscopy of FtsZ Cg or visualization of FtsZ Cg -GFP in C. glutamicum revealed that most cells showed one fluorescent band, most likely a ring, at the mid-cell, and some cells showed two fluorescent bands (septa of future daughter cells). When FtsZ Cg -GFP was expressed from Plac, FtsZ rings at mid-cell, or spirals, were also clearly visible in the aberrant cells; however, this morphology was not entirely due to GFP but also to the reduced levels of FtsZ expressed from Plac. Localization of FtsZ at the septum is not negatively regulated by the nucleoid, and therefore the well-known occlusion mechanism seems not to operate in C. glutamicum.

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Section: Discussionsupporting

confidence: 81%

Section: Discussionmentioning

confidence: 99%

Altered morphology produced by ftsZ expression in Corynebacterium glutamicum ATCC 13869

et al. 2005

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“…In E. coli, a low level overproduction of FtsZ causes minicell formation and higher levels inhibit cell division (Ward and Lutkenhaus 1985). In Rhizobium meliloti, overproduction of either of the two FtsZ proteins causes branching and swelling of cells (Latch and Margolin 1997). There is a similar requirement for control of the level of at least one other cell division protein.…”

Section: Discussionmentioning

confidence: 79%

Cell cycle-dependent transcriptional and proteolytic regulation of FtsZ in Caulobacter

Kelly

Sackett²,

Din³

et al. 1998

Genes & Development

197

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In the differentiating bacterium Caulobacter crescentus, the cell division initiation protein FtsZ is present in only one of the two cell types. Stalked cells initiate a new round of DNA replication immediately after cell division and contain FtsZ, whereas the progeny swarmer cells are unable to initiate DNA replication and do not contain FtsZ. We show that FtsZ expression is controlled by cell cycle-dependent transcription and proteolysis. Transcription of ftsZ is repressed in swarmer cells and is activated concurrently with the initiation of DNA replication. At the end of the DNA replication period, transcription of ftsZ decreases substantially. We show that the global cell cycle regulator CtrA is involved in the cell cycle control of ftsZ transcription. CtrA binds to a site that overlaps the ftsZ transcription start site. Removal of the CtrA-binding site results in transcription of the ftsZ promoter in swarmer cells. Decreasing the cellular concentration of CtrA increases ftsZ transcription and conversely, increasing the concentration of CtrA decreases ftsZ transcription. Because CtrA is present in swarmer cells, is degraded at the same time as ftsZ transcription begins, and reappears when ftsZ transcription decreases at the end of the cell cycle, we propose that CtrA is a repressor of ftsZ transcription. We show that proteolysis is an important determinant of cell type-specific distribution and cell cycle variation of FtsZ. FtsZ is stable when it is synthesized and assembles into the cytokinetic ring at the beginning of the cell cycle. After the initiation of cell division, the rate of FtsZ degradation increases as both the constriction site and the FtsZ ring decrease in diameter. When ftsZ is expressed constitutively from inducible promoters, the abundance of FtsZ still varies during the cell cycle. The coupling of transcription and proteolysis to cell division ensures that FtsZ is inherited only by the progeny cell that will begin DNA replication immediately after cell division.[Key Words: Caulobacter; FtsZ; cell division; proteolysis; cell cycle; differentiation] Received December 22, 1997; revised version accepted January 23, 1998.The mechanism by which cells coordinate DNA replication, cell growth, and cell division are not well understood (Donachie 1993;Vicente and Errington 1996). Research on cell division in Escherichia coli has pointed to the FtsZ protein as an essential determinant of the timing and the localization of cell division (Erickson 1995; Rothfield and Justice 1997). FtsZ is a tubulin-like GTPase that polymerizes and forms a cytokinetic ring associated with the cytoplasmic membrane at the site of cell division in bacteria (Bi and Lutkenhaus 1991) and archaea (Baumann and Jackson 1996;Margolin et al. 1996;Wang and Lutkenhaus 1996). Localization of FtsZ is likely to be the key event in assembly of the cell division apparatus. FtsZ recruits other cell division proteins to the site of division Ma et al. 1996) and may constrict, providing mechanical force for division. In E. coli, the concentr...

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“…We cannot deduce the molecular mechanism underlying this phenotype; however, the morphological changes resulting from the plasmid-mediated expression of S. meliloti DnaA are very similar to the pleomorphic cell shape phenotype reported for S. meliloti cells overexpressing FtsZ or when treated with DNA-damaging agents (Latch & Margolin, 1997). It would seem that the default pathway for a block in cell division that arises from perturbations in chromosome replication in this endosymbiont is a complex change in cell shape.…”

Section: Dnaa Binds To Predicted Binding Sites In the Heme-y02793 Intmentioning

confidence: 79%

The Sinorhizobium meliloti chromosomal origin of replication

2006

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The predicted chromosomal origin of replication (oriC) from the alfalfa symbiont Sinorhizobium meliloti is shown to allow autonomous replication of a normally non-replicating plasmid within S. meliloti cells. This is the first chromosomal replication origin to be experimentally localized in the Rhizobiaceae and its location, adjacent to hemE, is the same as for oriC in Caulobacter crescentus, the only experimentally characterized alphaproteobacterial oriC. Using an electrophoretic mobility shift assay and purified S. meliloti DnaA replication initiation protein, binding sites for DnaA were mapped in the S. meliloti oriC region. Mutations in these sites eliminated autonomous replication. S. meliloti that expressed DnaA from a plasmid lac promoter was observed to form pleomorphic filamentous cells, suggesting that cell division was perturbed. Interestingly, this cell phenotype is reminiscent of differentiated bacteroids found inside plant cells in alfalfa root nodules.

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Generation of buds, swellings, and branches instead of filaments after blocking the cell cycle of Rhizobium meliloti

Cited by 75 publications

References 36 publications

Altered morphology produced by ftsZ expression in Corynebacterium glutamicum ATCC 13869

Altered morphology produced by ftsZ expression in Corynebacterium glutamicum ATCC 13869

Cell cycle-dependent transcriptional and proteolytic regulation of FtsZ in Caulobacter

The Sinorhizobium meliloti chromosomal origin of replication

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