Cell cycle-specific changes in nucleoprotein complexes at a chromosomal replication origin.

Cassler, M R; Grimwade, Julia E.; Leonard, Alan C.

doi:10.1002/j.1460-2075.1995.tb00271.x

Cited by 129 publications

(189 citation statements)

References 46 publications

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“…It might act by binding to specific sites in promoter regions, thereby inducing DNA loops that allows interaction between RNA polymerase and distally bound regulatory proteins [Seong et al, 2002]. By a similar mechanism, it facilitates the assembly of initiation complexes at the replication origins of plasmids [Filutowicz and Inman, 1991;Stenzel et al, 1991] and bacterial chromosomes [Cassler et al, 1995].…”

Section: Mechansims Of Nucleoid Organizationmentioning

confidence: 99%

The bacterial nucleoid: A highly organized and dynamic structure

Thanbichler

Wang

Shapiro

2005

J of Cellular Biochemistry

121

101

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Recent advances in bacterial cell biology have revealed unanticipated structural and functional complexity, reminiscent of eukaryotic cells. Particular progress has been made in understanding the structure, replication, and segregation of the bacterial chromosome. It emerged that multiple mechanisms cooperate to establish a dynamic assembly of supercoiled domains, which are stacked in consecutive order to adopt a defined higher-level organization. The position of genetic loci on the chromosome is thereby linearly correlated with their position in the cell. SMC complexes and histone-like proteins continuously remodel the nucleoid to reconcile chromatin compaction with DNA replication and gene regulation. Moreover, active transport processes ensure the efficient segregation of sister chromosomes and the faithful restoration of nucleoid organization while DNA replication and condensation are in progress.

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Section: Mechansims Of Nucleoid Organizationmentioning

confidence: 99%

The bacterial nucleoid: A highly organized and dynamic structure

Thanbichler

Wang

Shapiro

2005

J of Cellular Biochemistry

121

101

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“…During the growth phase, the level of FIS drops, presumably because of the dilution of protein in the course of successive cellular divisions without degradation of the protein produced (Ball et al, 1992). It is conceivable that the sequential dissociation of FIS during the growth cycle from chromosomal sites with binding constants varying from micromolar to nanomolar range (Pan et al, 1996) could allow for correct timing of occupation by regulatory proteins of biologically important DNA loci, such as promoters, replication origins or recombination sequences (see for example Thompson et al, 1987;Cassler et al, 1995). Indeed, there is evidence that the effects of FIS on the initiation of DNA replication at oriC may depend on binding to secondary FIS-binding sites in addition to specific binding at a high-affinity site (Wold et al, 1996).…”

Section: Biological Implicationsmentioning

confidence: 99%

FIS modulates growth phase‐dependent topological transitions of DNA in Escherichia coli

Schneider

Travers

Muskhelishvili

1997

Molecular Microbiology

115

104

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SummaryThe Escherichia coli DNA-binding protein FIS serves as a DNA architectural factor in two unrelated enzymatic reactions, the site-specific inversion of DNA and transcriptional activation of stable RNA promoters. In both these processes, FIS facilitates the assembly and dynamic transitions of two structurally distinct nucleoprotein complexes. We have proposed previously that, in these systems, FIS stabilizes writhed DNA microloops by binding at multiple helically phased sites in DNA. However, FIS also binds and bends DNA at many non-specific sites and, at its maximum levels in the early exponential phase, FIS could potentially occupy a considerable part of the E. coli chromosome. Here, we show that fis affects growth phase-specific alterations in the supercoiling level of DNA. Expression of fis accelerates the accumulation of moderately supercoiled plasmids in stationary phase, which are stabilized by FIS after nutritional shift-up. In accordance with such a function, FIS modulates the relaxing and supercoiling activities of topoisomerases in vitro in a way that keeps DNA in a moderately supercoiled state. Our results suggest that the primary role of FIS is to modulate chromosomal dynamics during bacterial growth.

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“…The conservation of the IHF and Fis sites suggests their importance in the initiation of enterobacterial DNA replication and predicts that corresponding proteins exist in all these organisms. This notion is fully supported by genetic analysis (Lu et al, 1994) and by genomic footprinting (Cassler et al, 1995) in E. coli.…”

Section: Conservation Of Ihf and Fis Binding Sites In The Origins Of mentioning

confidence: 82%

“…Interestingly, however, both proteins were recently shown to be present at oriC in vivo (Cassler et al, 1995). The interactions of DnaA, IHF and Fis with oriC are dynamic.…”

Section: Introductionmentioning

confidence: 99%

“…The interactions of DnaA, IHF and Fis with oriC are dynamic. Fis-bound complex, present throughout the majority of the cell cycle, switches to an IHF-bound complex at the time of initiation of DNA replication coincident with increased binding of DnaA to box R1 and previously unoccupied box R3 (Cassler et al, 1995). Thus, it is clear that the initiation complex consists of IHF and DnaA and probably lacks Fis.…”

Section: Introductionmentioning

confidence: 99%

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Role of architectural elements in combinatorial regulation of initiation of DNA replication in Escherichia coli

Polaczek

Kwan

Liberles

et al. 1997

Molecular Microbiology

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SummaryBending of DNA is a prerequisite of site-specific recombination and gene expression in many regulatory systems involving the assembly of specific nucleoprotein complexes. We have investigated how the uniquely clustered Dam methylase sites, GATCs, in the origin of Escherichia coli replication (oriC ) and their methylation status modulate the geometry of oriC and its interaction with architectural proteins, such as integration host factor (IHF), factor for inversion stimulation (Fis) and DnaA initiator protein. We note that 3 of the 11 GATC sites at oriC are strategically positioned within the IHF protected region. Methylation of the GATCs enhances IHF binding and alters the IHF-induced bend at oriC. GATC motifs also contribute to intrinsic DNA curvature at oriC and the degree of bending is modulated by methylation. The IHF-induced bend at oriC is further modified by Fis protein and IHF affinity for its binding site may be impaired by protein(s) binding to GATCs within the IHF site. Thus, GATC sites at oriC affect the DNA conformation and GATCs, in conjunction with the proteininduced bends, are critical cis-acting elements in specifying proper juxtapositioning of initiation factors in the early steps of DNA replication.

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Cell cycle-specific changes in nucleoprotein complexes at a chromosomal replication origin.

Cited by 129 publications

References 46 publications

The bacterial nucleoid: A highly organized and dynamic structure

The bacterial nucleoid: A highly organized and dynamic structure

FIS modulates growth phase‐dependent topological transitions of DNA in Escherichia coli

Role of architectural elements in combinatorial regulation of initiation of DNA replication in Escherichia coli

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