E. coli SeqA protein binds oriC in two different methyl-modulated reactions appropriate to its roles in DNA replication initiation and origin sequestration

Slater, Steven; Wold, Sture; Lü, Min; Boye, Erik; Skarstad, Kirsten; Kleckner, Nancy

doi:10.1016/0092-8674(95)90272-4

Cited by 286 publications

(365 citation statements)

References 29 publications

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“…We speculate that there may be some interaction between DNA and the cytoplasmic membrane, similar to that found in rapidly growing E. coli (Slater et al, 1995). It is possible that the intercalation of DNA may release the cytoplasmic membrane from the DNA to allow fusion.…”

mentioning

confidence: 91%

Thermococcus coalescens sp. nov., a cell-fusing hyperthermophilic archaeon from Suiyo Seamount

Kuwabara

Minaba

Iwayama

et al. 2005

International Journal of Systematic and Evolutionary Microbiology

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A cell-fusing hyperthermophilic archaeon was isolated from hydrothermal fluid obtained from Suiyo Seamount of the Izu-Bonin Arc. The isolate, TS1 T , is an irregular coccus, usually 0?5-2 mm in diameter and motile with a polar tuft of flagella. Cells in the exponential phase of growth fused at room temperature in the presence of DNA-intercalating dye to become as large as 5 mm in diameter. Fused cells showed dark spots that moved along in the cytoplasm. Large cells with a similar appearance were also observed upon culture at 87 6C, suggesting the occurrence of similar cell fusions during growth. Transmission electron microscopy revealed that cells in the exponential phase possessed a thin and electron-lucent cell envelope that could be lost subsequently during culture. The fragile cell envelope must be related to cell fusion. The cells grew at 57-90 6C, pH 5?2-8?7 and at NaCl concentrations of 1?5-4?5 %, with the optima being 87 6C, pH 6?5 and 2?5 % NaCl. The isolate was an anaerobic chemo-organotroph that grew on either yeast extract or tryptone as the sole growth substrate. The genomic DNA G+C content was 53?9 mol%. Phylogenetic analysis based on 16S rRNA gene sequencing indicated that the isolate was closely related to Thermococcus species. However, no significant DNA-DNA hybridization was observed between genomic DNA of strain TS1 T and phylogenetically related Thermococcus species. We propose that isolate TS1 T represents a novel species, Thermococcus coalescens sp. nov., with the name reflecting the cell fusion activity observed in the strain. The type strain is TS1 T (=JCM 12540 T =DSM 16538 T ).

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mentioning

confidence: 91%

Thermococcus coalescens sp. nov., a cell-fusing hyperthermophilic archaeon from Suiyo Seamount

Kuwabara

Minaba

Iwayama

et al. 2005

International Journal of Systematic and Evolutionary Microbiology

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“…This process functions by specific inactivation of newly replicated origins by the protein SeqA (Slater et al, 1995). Newly synthesized DNA in E. coli is hemimethylated, methylated (by Dam methylase) on the old strand and unmethylated on the new strand, and SeqA binds preferentially to hemimethylated DNA (Brendler et al, 1995;Slater et al, 1995).…”

Section: Introductionmentioning

confidence: 99%

Replication patterns and organization of replication forks in Vibrio cholerae

2011

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We have investigated the replication patterns of the two chromosomes of the bacterium Vibrio cholerae grown in four different media. By combining flow cytometry and quantitative real-time PCR with computer simulations, we show that in rich media, V. cholerae cells grow with overlapping replication cycles of both the large chromosome (ChrI) and the small chromosome (ChrII). In Luria-Bertani (LB) medium, initiation occurs at four copies of the ChrI origin and two copies of the ChrII origin. Replication of ChrII was found to occur at the end of the ChrI replication period in all four growth conditions. Novel cell-sorting experiments with marker frequency analysis support these conclusions. Incubation with protein synthesis inhibitors indicated that the potential for initiation of replication of ChrII was present at the same time as that of ChrI, but was actively delayed until much of ChrI was replicated. Investigations of the localization of SeqA bound to new DNA at replication forks indicated that the forks were co-localized in pairs when cells grew without overlapping replication cycles and in higher-order structures during more rapid growth. The increased degree of fork organization during rapid growth may be a means by which correct segregation of daughter molecules is facilitated.

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“…GATC methylation and its role in initiation of DNA replication has puzzled researchers for years. Participation of GATC sites in negative regulation, at the level of hemimethylation, has been unambiguously supported by a number of experiments (Russell and Zinder, 1987;Ogden et al, 1988;Campbell and Kleckner, 1990;Herrick et al, 1994;Lu et al, 1994;Slater et al, 1995;Crooke, 1995 for review). dam mutants, although defective in the timing of initiation, are viable (Boye et al, 1993).…”

Section: Introductionmentioning

confidence: 91%

“…Outer membrane fractions and SeqA protein appear to have a high affinity for the GATC located at the BamHI site at position 92 of oriC within the IHF protected region (Kusano et al, 1984;Slater et al, 1995; see Discussion). Thus, IHF and other methyl-directed binding proteins may antagonize each other's binding at the BamHI site.…”

Section: Conformation Of the Ihf/oric Complexmentioning

confidence: 99%

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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E. coli SeqA protein binds oriC in two different methyl-modulated reactions appropriate to its roles in DNA replication initiation and origin sequestration

Cited by 286 publications

References 29 publications

Thermococcus coalescens sp. nov., a cell-fusing hyperthermophilic archaeon from Suiyo Seamount

Thermococcus coalescens sp. nov., a cell-fusing hyperthermophilic archaeon from Suiyo Seamount

Replication patterns and organization of replication forks in Vibrio cholerae

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

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