title: The arc two-component signal transduction system inhibits in vitro Escherichia coli chromosomal initiation.
abstract: Under anaerobic growth conditions, Escherichia coli operates a two-component signal transduction system, termed Arc, that consists of ArcB protein, a transmembrane sensor kinase and ArcA protein, the cognate response regulator. In response to low oxygen levels, autophosphorylated ArcB phosphorylates ArcA, and the resulting phosphorylated ArcA (ArcA-P) functions as a transcriptional regulator of the genes necessary to maintain anaerobic growth. Under anaerobic conditions, cells maintain a slow growth rate, suggesting that the initiation of chromosomal replication is regulated to reduce the initiation frequency. DNase I footprinting experiments revealed that ArcA-P binds to the left region of the chromosomal origin, oriC. ArcA-P did not affect the in vitro replication of plasmid DNA containing the ColE1 origin nor the in vitro replication of viral DNAs; however, ArcA-P specifically inhibited in vitro E. coli chromosomal replication. This inhibition was caused by the prevention of open complex formation, a necessary step in the initiation of chromosomal replication. Our in vitro results suggest that the Arc two-component system participates in regulating chromosomal initiation under anaerobic growth conditions.
authors.affiliation: Institute of Molecular Biology and Genetics, School of Biological Sciences, Seoul National University, Seoul 151-742, Korea.
authors.forename: Y S
authors.initials: YS
authors.lastname: Lee
authors.forename: J S
authors.initials: JS
authors.lastname: Han
authors.forename: Y
authors.initials: Y
authors.lastname: Jeon
authors.forename: D S
authors.initials: DS
authors.lastname: Hwang
mesh_terms: D001425:Bacterial Outer Membrane Proteins / Q000737:chemistry*; D001426:Bacterial Proteins / Q000378:metabolism; D002455:Cell Division; D002875:Chromosomes / Q000378:metabolism*; D004247:DNA / Q000378:metabolism; D004261:DNA Replication; D004268:DNA-Binding Proteins / Q000378:metabolism; D003850:Deoxyribonuclease I / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D004591:Electrophoresis, Polyacrylamide Gel; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism*; D029968:Escherichia coli Proteins; D008565:Membrane Proteins / Q000502:physiology*; D051738:Origin Recognition Complex; D010100:Oxygen / Q000378:metabolism; D010766:Phosphorylation; D010957:Plasmids / Q000378:metabolism; D011485:Protein Binding; D011494:Protein Kinases / Q000502:physiology*; D012097:Repressor Proteins; D015398:Signal Transduction; D014158:Transcription, Genetic; D014764:Viral Proteins / Q000378:metabolism
chemical_list: D001425:Bacterial Outer Membrane Proteins; D001426:Bacterial Proteins; D004268:DNA-Binding Proteins; C066312:DnaA protein, Bacteria; D029968:Escherichia coli Proteins; D008565:Membrane Proteins; C114650:OriC chromosomal replication origin; D051738:Origin Recognition Complex; D012097:Repressor Proteins; D014764:Viral Proteins; C041610:arcA protein, E coli; C068863:argP protein, E coli; D004247:DNA; D011494:Protein Kinases; C065271:arcB protein, E coli; D003850:Deoxyribonuclease I; D010100:Oxygen