title: Role of AcsR in expression of the acetyl-CoA synthetase gene in Vibrio vulnificus.
abstract: BACKGROUND
  VarS/VarA is one of the global factors regulating diverse aspects of the metabolism and virulence of bacteria including pathogenic Vibrio spp. An experiment to identify the VarS/VarA-regulon in V. vulnificus revealed that a putative LuxR-type transcriptional regulator was down-regulated in ΔvarA mutant. To investigate the roles of this regulatory cascade, the target gene regulated by a LuxR-regulator was identified and its expression was characterized.
  
  
  RESULTS
  Transcriptomic analysis of the mutant deficient in this LuxR-type regulator showed that the acsA gene encoding acetyl-CoA synthetase was down-regulated. Thus, this regulator was named AcsR for "regulator of acetyl-CoA synthetase". A putative histidine kinase gene, acsS, was located five ORFs downstream of the acsR gene. Expression of an acsA::luxAB transcriptional fusion was decreased in both ΔacsR and ΔacsS mutants. Similar to a ΔacsA mutant, strains carrying deletions either in acsR or acsS grew slowly than wild type in a minimal medium with acetate as a sole carbon source. Growth defect of the ΔacsR strain in acetate-minimal medium was restored by complementation. To investigate if AcsR directly regulates acsA expression, in vitro-gel shift assays were performed using the recombinant AcsR and the regulatory region of the acsA gene, showing that AcsR specifically bound the upstream region of the acsA ORF.
  
  
  CONCLUSIONS
  This study indicates that the VarS/VarA system plays a role in V. vulnificus metabolism via regulating AcsR, which in turn controls acetate metabolism by activating the transcription of the acetyl-CoA synthetase gene.
authors.affiliation: Department of Environmental Medical Biology and Institute of Tropical Medicine, Brain Korea 21 PLUS Project for Medical Science, Yonsei University, Seoul, 120-752, South Korea. MJKIM55@yuhs.ac.
authors.forename: Min Jung
authors.initials: MJ
authors.lastname: Kim
authors.affiliation: Department of Environmental Medical Biology and Institute of Tropical Medicine, Brain Korea 21 PLUS Project for Medical Science, Yonsei University, Seoul, 120-752, South Korea. zhuri@yuhs.ac.
authors.forename: Juri
authors.initials: J
authors.lastname: Kim
authors.affiliation: Department of Environmental Medical Biology and Institute of Tropical Medicine, Brain Korea 21 PLUS Project for Medical Science, Yonsei University, Seoul, 120-752, South Korea. HYLEE0617@yuhs.ac.
authors.forename: Hye Yeon
authors.initials: HY
authors.lastname: Lee
authors.affiliation: Department of Environmental Medical Biology and Institute of Tropical Medicine, Brain Korea 21 PLUS Project for Medical Science, Yonsei University, Seoul, 120-752, South Korea. no1081hj@naver.com.
authors.forename: Hyeon Jin
authors.initials: HJ
authors.lastname: Noh
authors.affiliation: Department of Life Science, Sogang University, Seoul, 121-742, South Korea. kyuholee@sogang.ac.kr.
authors.forename: Kyu-Ho
authors.initials: KH
authors.lastname: Lee
authors.affiliation: Department of Environmental Medical Biology and Institute of Tropical Medicine, Brain Korea 21 PLUS Project for Medical Science, Yonsei University, Seoul, 120-752, South Korea. sjpark615@yuhs.ac.
authors.forename: Soon-Jung
authors.initials: SJ
authors.lastname: Park
mesh_terms: D000106:Acetate-CoA Ligase / Q000378:metabolism*; D019677:Artificial Gene Fusion; D003470:Culture Media / Q000737:chemistry; D004269:DNA, Bacterial / Q000378:metabolism; D024202:Electrophoretic Mobility Shift Assay; D017353:Gene Deletion; D020869:Gene Expression Profiling; D015964:Gene Expression Regulation, Bacterial; D017930:Genes, Reporter; D005816:Genetic Complementation Test; D008156:Luciferases / Q000032:analysis / Q000235:genetics; D011485:Protein Binding; D014157:Transcription Factors / Q000172:deficiency / Q000378:metabolism*; D041261:Vibrio vulnificus / Q000201:enzymology* / Q000254:growth & development
chemical_list: D003470:Culture Media; D004269:DNA, Bacterial; D014157:Transcription Factors; D008156:Luciferases; D000106:Acetate-CoA Ligase