Toporegulation of bacterial division according to the nucleoid occlusion model

Woldringh, Conrad L.; Mulder, E; Huls, P. G.; Vischer, Norbert O. E.

doi:10.1016/0923-2508(91)90046-d

Cited by 160 publications

(131 citation statements)

References 22 publications

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“…In E. coli and vegetatively growing B. subtilis, the timing of division is regulated so that it follows the replication and segregation of sister chromosomes and division occurs at mid-cell in the DNA-free space between the partitioned nucleoids. The 'nucleoid occlusion' model, first proposed over a decade ago by Woldringh et al (1991), in combination with the Min system could provide a dual mechanism for targeting the division machinery to mid-cell and simultaneously protecting the nucleoid from bisection by aberrantly forming septa. Wu & Errington (2004) have recently reported the identification of a novel nucleoid occlusion protein, Noc, which prevents the division machinery from assembling in the vicinity of the nucleoid.…”

Section: Coordination Of Partitioning and Division: The Nucleoid Occlmentioning

confidence: 99%

Towards understanding the molecular basis of bacterial DNA segregation

Leonard

Møller‐Jensen

Löwe

2005

Phil. Trans. R. Soc. B

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Bacteria ensure the fidelity of genetic inheritance by the coordinated control of chromosome segregation and cell division. Here, we review the molecules and mechanisms that govern the correct subcellular positioning and rapid separation of newly replicated chromosomes and plasmids towards the cell poles and, significantly, the emergence of mitotic-like machineries capable of segregating plasmid DNA. We further describe surprising similarities between proteins involved in DNA partitioning (ParA/ParB) and control of cell division (MinD/MinE), suggesting a mechanism for intracellular positioning common to the two processes. Finally, we discuss the role that the bacterial cytoskeleton plays in DNA partitioning and the missing link between prokaryotes and eukaryotes that is bacterial mechano-chemical motor proteins.

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Section: Coordination Of Partitioning and Division: The Nucleoid Occlmentioning

confidence: 99%

Towards understanding the molecular basis of bacterial DNA segregation

Leonard

Møller‐Jensen

Löwe

2005

Phil. Trans. R. Soc. B

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“…The nucleoid occlusion model (Mulder & Woldringh, 1989Woldringh et al,, 1991) proposes that the nucleoid produces a signal that inhibits cell division by blocking murein synthesis. This model is a complex one with many additional elements, but it is an incomplete model because it does not specify how the nucleoids ' know' when and how far to move from each other after the sister nuclei have become separated.…”

Section: Current Modelsmentioning

confidence: 99%

A physical basis for the precise location of the division site of rod-shaped bacteria: the Central Stress Model

Koch

Höltje

1995

Microbiology

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There are difficulties with all published models that attempt to explain how rod-shaped bacteria locate their midpoint in preparation for the next cell division. Many bacteria find their middle quite accurately. This evenness of partition has been measured cytologically and is implied by the persistence of synchrony under certain circumstances. Previously, a number of models for the control of cell division have been proposed based on aspects of molecular genetics, ultrastructure measurements, or biochemical kinetics. This paper points out that none of the models in spite of their quite different natures can explain the precision of the location of the division site. Here, the 'Central Stress Model' is proposed which depends on the partition of wall tension between the cytoplasmic membrane (CM) and the murein layer in such a way that the CM at the centre of the rod experiences a higher stress than near the poles and that this peak stress increases through the cell cycle. The model assumes that: (i) murein is not incorporated at an established pole but is incorporated diffusely over the sidewall and intensely at sites of cell constriction; (ii) C M is synthesized over the entire cell wall; (iii) the murein and C M layers are attached non-covalently to each other, and interact physically with each other; (iv) this differential location of synthesis leads to a 'tug-ofwar' that creates differential stresses that peak at the cell centre. Because of the fluid nature of the phospholipid bilayer there is a flux of lipid from the established poles towards the cell centre as the murein sidewall elongates. The flux from the pole lowers the tension in the C M at the ends of the sidewalls and creates a peak tension in the centre. Cells also have a discontinuity in the stresses in the murein at the junction of the curved pole with the cylindrical region of the cell wall (a doubling of the hoop stress above the axial stress). Thus in addition to the midpoint of the cell, these junctions between the polar caps and the cylindrical part of the cell wall are characterized by an abrupt change in the surface stress and we suggest that this can trigger cell division at these junctions to form a chromosome-less minicell. Two other assumptions of the model are that the cell has a membrane-associated system to sense the stress, and to trigger cell division locally when a threshold has been reached. It is suggested that there is a special twolcomponent sensory system responding to tension in the CM. As the cell cycle progresses, and the stress in the centre of the cell exceeds some threshold, a system molecule triggers a cell division event at that site. Like other two-component systems, the sensory component of this two-component system is assumed to be distributed all over the CM. It is also assumed that when the sensory component is triggered it also causes local changes that ensure that division occurs at that site. Consequently, this model can explain why sister cells have very nearly the same size (length, volume, or biomass) and w...

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“…A diverse repertoire of FtsZ-binding regulatory proteins has evolved that affect FtsZ localization and polymerization to ensure that the Z ring is created at the correct place and time during cell division (2)(3)(4)(18)(19)(20). In the model bacteria E. coli and Bacillus subtilis, two FtsZ regulatory systems, the Min system (21)(22)(23)(24)(25) and nucleoid occlusion (NO) (26)(27)(28), play key roles in controlling temporal and spatial establishment of the Z ring. The Min system prevents Z-ring formation at the cell poles, and NO prevents Z rings from forming over chromosomal DNA (Fig.…”

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confidence: 99%

Structures of the nucleoid occlusion protein SlmA bound to DNA and the C-terminal domain of the cytoskeletal protein FtsZ

Schumacher

Zhang

2016

Proc. Natl. Acad. Sci. U.S.A.

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Cell division in most prokaryotes is mediated by FtsZ, which polymerizes to create the cytokinetic Z ring. Multiple FtsZ-binding proteins regulate FtsZ polymerization to ensure the proper spatiotemporal formation of the Z ring at the division site. The DNA-binding protein SlmA binds to FtsZ and prevents Z-ring formation through the nucleoid in a process called "nucleoid occlusion" (NO). As do most FtsZ-accessory proteins, SlmA interacts with the conserved C-terminal domain (CTD) that is connected to the FtsZ core by a long, flexible linker. However, SlmA is distinct from other regulatory factors in that it must be DNA-bound to interact with the FtsZ CTD. Few structures of FtsZ regulator-CTD complexes are available, but all reveal the CTD bound as a helix. To deduce the molecular basis for the unique SlmA-DNA-FtsZ CTD regulatory interaction and provide insight into FtsZ-regulator protein complex formation, we determined structures of Escherichia coli, Vibrio cholera, and Klebsiella pneumonia SlmA-DNA-FtsZ CTD ternary complexes. Strikingly, the FtsZ CTD does not interact with SlmA as a helix but binds as an extended conformation in a narrow, surface-exposed pocket formed only in the DNA-bound state of SlmA and located at the junction between the DNA-binding and C-terminal dimer domains. Binding studies are consistent with the structure and underscore key interactions in complex formation. Combined, these data reveal the molecular basis for the SlmA-DNA-FtsZ interaction with implications for SlmA's NO function and underscore the ability of the FtsZ CTD to adopt a wide range of conformations, explaining its ability to bind diverse regulatory proteins.n Escherichia coli cell division is directed by a cytoskeletal element called the "Z ring," which is formed at the cell membrane by the tubulin-like protein, FtsZ (1-5). FtsZ is an ancient and highly conserved protein that mediates cell division in most bacteria, many archaea, chloroplasts, and the mitochondria of primitive eukaryotes (5). FtsZ consists of three main domains: a globular core that harbors the GTP-binding site, a flexible C-terminal linker (CTL) that is ∼50 residues long in E. coli but is of variable length among FtsZ homologs, and a C-terminal domain (CTD) comprised of a highly conserved set of residues followed by a short and less conserved, variable (CTV) region (Fig. S1A) (6-9). FtsZ self-assembles into linear protofilaments in a GTP-dependent manner by interactions between its globular domains, and data suggest that loosely arranged lateral contacts between protofilaments mediate the formation of the Z ring at the cell center (10-16). Notably, the intracellular levels of FtsZ remain largely unchanged during the cell cycle and exceed the critical concentration required for Z-ring formation (17). A diverse repertoire of FtsZ-binding regulatory proteins has evolved that affect FtsZ localization and polymerization to ensure that the Z ring is created at the correct place and time during cell division (2)(3)(4)(18)(19)(20). In the model bacteria E. coli a...

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Toporegulation of bacterial division according to the nucleoid occlusion model

Cited by 160 publications

References 22 publications

Towards understanding the molecular basis of bacterial DNA segregation

Towards understanding the molecular basis of bacterial DNA segregation

A physical basis for the precise location of the division site of rod-shaped bacteria: the Central Stress Model

Structures of the nucleoid occlusion protein SlmA bound to DNA and the C-terminal domain of the cytoskeletal protein FtsZ

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