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seqA negative modulator of initiation of replication [ Escherichia coli str. K-12 substr. MG1655 ]

Gene ID: 945272, updated on 23-Apr-2026
Official Symbol
seqA
Official Full Name
negative modulator of initiation of replication
Primary source
ECOCYC:EG12197
Locus tag
b0687
See related
ASAP:ABE-0002343
Gene type
protein coding
RefSeq status
REVIEWED
Organism
Escherichia coli str. K-12 substr. MG1655 (strain: K-12, substrain: MG1655)
Lineage
Bacteria; Pseudomonadati; Pseudomonadota; Gammaproteobacteria; Enterobacterales; Enterobacteriaceae; Escherichia
Also known as
ECK0675; hsm-1
Summary
SeqA is required for the membrane binding of hemimethylated oriC in vitro. [More information is available at EcoGene: EG12197]. The SeqA protein is a negative modulator of the initiation of chromosome replication and is required for sequestration of oriC, ensuring a single round of chromosome replication per cell cycle . [More information is available at EcoCyc: EG12197].
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Sequence:
NC_000913.3 (712987..713532)

NC_000913.3Genomic Context describing neighboring genes Neighboring gene ribbon-helix-helix domain-containing protein YbfE Neighboring gene esterase Neighboring gene phosphoglucomutase Neighboring gene lipoprotein YbfP

Genomic Sequence:
NC_000913.3

Go to nucleotide: Graphics FASTA GenBank

Related articles in PubMed

  1. Binding of SeqA protein to hemi-methylated GATC sequences enhances their interaction and aggregation properties. Han JS, et al. J Biol Chem, 2004 Jul 16. PMID 15151991
  2. SeqA protein aggregation is necessary for SeqA function. Lee H, et al. J Biol Chem, 2001 Sep 14. PMID 11457824
  3. Insights into negative modulation of E. coli replication initiation from the structure of SeqA-hemimethylated DNA complex. Guarné A, et al. Nat Struct Biol, 2002 Nov. PMID 12379844
  4. Identification of functional domains of the Escherichia coli SeqA protein. Fujikawa N, et al. Biochem Biophys Res Commun, 2003 Jan 17. PMID 12507506
  5. Excess SeqA prolongs sequestration of oriC and delays nucleoid segregation and cell division. Bach T, et al. EMBO J, 2003 Jan 15. PMID 12514137, Free PMC Article

See all (105) citations in PubMed

GeneRIFs: Gene References Into Functions

What's a GeneRIF?
  1. Topoisomerase IV tracks behind the replication fork and the SeqA complex during DNA replication in Escherichia coli.
    Title: Topoisomerase IV tracks behind the replication fork and the SeqA complex during DNA replication in Escherichia coli.
  2. Data indicate that the SeqA protein is localized at midcell for most of the D-period, but colocalizes with the origin region before cell division and initiation of replication.
    Title: Dynamic Escherichia coli SeqA complexes organize the newly replicated DNA at a considerable distance from the replisome.
  3. Data suggest that, in the absence of SeqA, the sister-chromatid cohesion 'safety spacer' is destabilized and completely disappears if the replication fork is inhibited.
    Title: Replication fork inhibition in seqA mutants of Escherichia coli triggers replication fork breakage.
  4. We propose that SeqA binding results in loose inter-duplex junctions that are resistant to Topo IV cleavage
    Title: Regulation of sister chromosome cohesion by the replication fork tracking protein SeqA.
  5. Cell cycle analysis showed that loss of SeqA from the old replication forks did not occur at initiation of the new forks, but instead occurs at a time point coinciding with the end of SeqA-dependent origin sequestration.
    Title: Replication fork movement and methylation govern SeqA binding to the Escherichia coli chromosome.
  6. The number of SeqA foci is not directly governed by the number of replication forks, and supports the idea that new DNA may be 'captured' by existing SeqA structures.
    Title: Growth rate dependent numbers of SeqA structures organize the multiple replication forks in rapidly growing Escherichia coli.
  7. well-defined SeqA structures are not found in situations of extensive replication fork repair
    Title: A reduction in ribonucleotide reductase activity slows down the chromosome replication fork but does not change its localization.
  8. An examination of the molecular model of Escherichia coli SeqA protein, a negative regulator of chromosome DNA replication which prevents the overinitiation of replication.
    Title: Modeling of the full-length Escherichia coli SeqA protein, in complex with DNA.
  9. seqA mutants have increased LPS phosphorylation and exhibit high levels of chromosomal fragmentation.
    Title: Reduced lipopolysaccharide phosphorylation in Escherichia coli lowers the elevated ori/ter ratio in seqA mutants.
  10. These results indicate that unlike oriC, SeqA modulates lambda DNA replication indirectly, most probably by influencing the stability of the lambda replication complex and the transcriptional activation of ori lambda.
    Title: Modulation of lambda plasmid and phage DNA replication by Escherichia coli SeqA protein.
Submit: New GeneRIF Correction See all GeneRIFs (18)
Products Interactant Other Gene Complex Source Pubs Description

Homology

Gene Ontology Provided by EcoCyc

Function Evidence Code Pubs
enables DNA binding IEA
Inferred from Electronic Annotation
more info
  
enables DNA replication origin binding IDA
Inferred from Direct Assay
more info
 PubMed 
enables double-stranded methylated DNA binding IDA
Inferred from Direct Assay
more info
 PubMed 
enables hemi-methylated DNA-binding IDA
Inferred from Direct Assay
more info
 PubMed 
enables identical protein binding IPI
Inferred from Physical Interaction
more info
 PubMed 
enables protein binding IPI
Inferred from Physical Interaction
more info
 PubMed 
enables protein homodimerization activity IDA
Inferred from Direct Assay
more info
 PubMed 
enables sequence-specific DNA binding IEA
Inferred from Electronic Annotation
more info
  
Process Evidence Code Pubs
involved_in negative regulation of DNA-templated DNA replication initiation IEA
Inferred from Electronic Annotation
more info
  
acts_upstream_of_or_within negative regulation of DNA-templated DNA replication initiation IGI
Inferred from Genetic Interaction
more info
 PubMed 
acts_upstream_of_or_within negative regulation of DNA-templated DNA replication initiation IMP
Inferred from Mutant Phenotype
more info
 PubMed 
involved_in regulation of DNA-templated transcription IEA
Inferred from Electronic Annotation
more info
  
acts_upstream_of_or_within response to radiation IMP
Inferred from Mutant Phenotype
more info
 PubMed 
acts_upstream_of_or_within sister chromatid cohesion IGI
Inferred from Genetic Interaction
more info
 PubMed 
Component Evidence Code Pubs
part_of SeqA-DNA complex IDA
Inferred from Direct Assay
more info
 PubMed 
located_in cytoplasm IEA
Inferred from Electronic Annotation
more info
  
located_in cytosol IDA
Inferred from Direct Assay
more info
 PubMed 
part_of protein-containing complex IDA
Inferred from Direct Assay
more info
 PubMed 
Preferred Names
negative modulator of initiation of replication

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Genome Annotation

The following sections contain reference sequences that belong to a specific genome build. Explain

Reference assembly

Genomic

  1. NC_000913.3 Reference assembly

    Range
    712987..713532
    Download
    GenBank, FASTA, Sequence Viewer (Graphics)

mRNA and Protein(s)

  1. NP_415213.1 negative modulator of initiation of replication

    See identical proteins and their annotated locations for NP_415213.1

    Status: REVIEWED

    UniProtKB/TrEMBL
    D3GXD9
    Conserved Domains (1) summary
    PRK11187
    Location:1 → 181
    PRK11187; replication initiation negative regulator SeqA
Nucleotide Protein
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