Disease relevance of seqA

• Interestingly, seqA is only present in a few DamMT-specifying proteobacteria [1].
• SeqA: a negative modulator of replication initiation in E. coli [2].
• SeqA specifically activates the bacteriophage lambda pR promoter while revealing no significant effect on the activity of another lambda promoter, pL [3].

Psychiatry related information on seqA

• Mutational analysis of the multimerization domain indicates that, in addition to multimerization of SeqA polypeptides, this domain contributes to the ability of SeqA to bind to a pair of hemi-sites and to its cooperative behavior [4].

High impact information on seqA

• E. coli SeqA protein binds oriC in two different methyl-modulated reactions appropriate to its roles in DNA replication initiation and origin sequestration [5].
• Direct interaction of SeqA protein with the replication origin is likely to be involved in both replication initiation and sequestration [5].
• We propose a model of a SeqA filament interacting with multiple GATC sites that accounts for both origin sequestration and chromosome organization [6].
• Escherichia coli SeqA binds clusters of transiently hemimethylated GATC sequences and sequesters the origin of replication, oriC, from methylation and premature reinitiation [6].
• SeqA overproduction also interfered with the segregation of sister nucleoids and caused a delay in cell division [7].

Chemical compound and disease context of seqA

• The SeqA protein binds to the post-replicative forms of the origins of replication of the Escherichia coli chromosome (oriC) and the P1 plasmid (P1oriR) at hemimethylated GATC adenine methylation sites [8].

Biological context of seqA

• We suggest that the SeqA protein's role in maintaining the eclipse is tied to a function in chromosome organization [9].
• In comparison with the effect of HU on plasmid topology, SeqA seemed to act more cooperatively [10].
• Mutations that disrupt filament formation lead to asynchronous DNA replication, but the resulting SeqA dimer can still bind two GATC sites separated from 5 to 34 base pairs [6].
• Production of ATP-DnaA depended on concomitant protein synthesis, but not on SOS response, Dam or SeqA [11].
• Role of SeqA and Dam in Escherichia coli gene expression: a global/microarray analysis [12].

Anatomical context of seqA

• High-affinity binding of hemimethylated oriC by Escherichia coli membranes is mediated by a multiprotein system that includes SeqA and a newly identified factor, SeqB [13].

Associations of seqA with chemical compounds

• Using a bacterial two-hybrid system, we demonstrate that the N-terminal region of SeqA, especifically the 9th amino acid residue, glutamic acid, is required for functional SeqA-SeqA interaction [14].
• Using gel-filtration chromotography and glycerol gradient sedimentation, we demonstrate that SeqA exists as a homotetramer [14].
• Although the SeqA(E9K) mutant protein, containing lysine rather than glutamic acid at the 9th amino acid residue, exists as a tetramer, the mutant protein binds to hemimethylated DNA with altered binding patterns as compared with wild-type SeqA [14].
• SeqA function seems to be distinguished from the control of DnaA protein by adenine nucleotide binding [15].
• The mukB mutant was oversensitive to novobiocin and this susceptibility was suppressed in the mukBseqA strain, suggesting possible roles of MukB and SeqA in maintaining chromosome topology [16].

Analytical, diagnostic and therapeutic context of seqA

• Using immunofluorescence microscopy, we have found that SeqA protein, a regulator of replication initiation, is localized as discrete fluorescent foci in E. coli wild-type cells [17].
• The SeqA protein was absolutely required for the eclipse, and DnaA titration studies suggested that the SeqA protein prevented the binding of multiple DnaA molecules on oriC (initial complex formation) [9].
• High-density oligonucleotide arrays were used to monitor global transcription patterns in Escherichia coli with various levels of Dam and SeqA proteins [12].
• Immunoprecipitation of the fusion from cell extracts using anti-Gfp antibody indicated that the fusion was assembled with the wild-type SeqA protein [18].
• DNA microarray analyses showed that the level of initiation in rapidly growing cells that lack datA was indistinguishable from that in wild-type cells, and that the absence of SeqA protein caused only a modest increase in initiation, in agreement with flow-cytometry data [19].

References