title: Expression and Functions of CreD, an Inner Membrane Protein in Stenotrophomonas maltophilia.
abstract: CreBC is a highly conserved two-component regulatory system (TCS) in several gram-negative bacteria, including Escherichia coli, Aeromonas spp., Pseudomonas aeruginosa, and Stenotrophomonas maltophilia. CreD is a conserved gene that encodes a predicted inner-membrane protein and is located near the creBC loci. Activation of CreBC increases creD expression; therefore, creD expression is generally used as a measure of CreBC activation in E. coli, Aeromonas spp., and P. aeruginosa systems. In this article, we aim to elucidate the expression of creD and further to investigate its functions in S. maltophilia. In spite of a short intergenic region of 81 bp between creBC and creD, creD is expressed separately from the adjacent creBC operon and from a promoter immediately upstream of creD (PcreD) in S. maltophilia. We found that the promoter activity of PcreD is negatively regulated by the creBC TCS, positively regulated by the bacterial culture density, and not affected by β-lactams. Furthermore, creD expression is not significantly altered in the presence of the phosphor-mimic variant of CreB, CreB(D55E), which mimics activated CreB. The functions of CreD of S. maltophilia were assessed by comparison among the following: wild-type KJ; the creD isogenic mutant, KJΔCreD; and the complementary strain, KJΔCreD(pCreD). The mutant lacking creD had cell division defects and aberrations in cell envelope integrity, which then triggered the σE-mediated envelope stress response. Thus, the results indicated that CreD plays a critical role in the maintenance of envelope integrity.
authors.affiliation: Department of Biotechnology and Laboratory Science in Medicine, National Yang-Ming University, Taipei, Taiwan.
authors.forename: Hsin-Hui
authors.initials: HH
authors.lastname: Huang
authors.affiliation: Division of Infectious Diseases, Department of Medicine, Taipei Veterans General Hospital, Taipei, Taiwan.|School of Medicine, National Yang-Ming University, Taipei, Taiwan.
authors.forename: Yi-Tsung
authors.initials: YT
authors.lastname: Lin
authors.affiliation: Department of Biotechnology and Laboratory Science in Medicine, National Yang-Ming University, Taipei, Taiwan.
authors.forename: Wei-Ching
authors.initials: WC
authors.lastname: Chen
authors.affiliation: Department of Biotechnology and Laboratory Science in Medicine, National Yang-Ming University, Taipei, Taiwan.
authors.forename: Yi-Wei
authors.initials: YW
authors.lastname: Huang
authors.affiliation: Department of Life Science, Institute of Ecology and Evolutionary Biology and TechComm-5, College of Life Science, National Taiwan University, Taipei, Taiwan.
authors.forename: Shiang-Jiuun
authors.initials: SJ
authors.lastname: Chen
authors.affiliation: Department of Biotechnology and Laboratory Science in Medicine, National Yang-Ming University, Taipei, Taiwan.
authors.forename: Tsuey-Ching
authors.initials: TC
authors.lastname: Yang
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D002462:Cell Membrane / Q000235:genetics; D017353:Gene Deletion; D015964:Gene Expression Regulation, Bacterial; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D008826:Microbial Sensitivity Tests; D005810:Multigene Family; D016297:Mutagenesis, Site-Directed; D011401:Promoter Regions, Genetic; D020615:Stenotrophomonas maltophilia / Q000378:metabolism*; D014640:Vancomycin / Q000494:pharmacology
chemical_list: D001426:Bacterial Proteins; D008565:Membrane Proteins; D014640:Vancomycin