title: Characterization of a spermine/spermidine transport system reveals a novel DNA sequence duplication in Neisseria gonorrhoeae.
abstract: During infection, Neisseria gonorrhoeae, the causative agent of the sexually transmitted disease gonorrhea, comes into contact with numerous host compounds including polyamines (e.g. spermine and spermidine). Here, we show that spermine and spermidine concentrations in the growth medium decrease to undetectable levels in the presence of gonococci over time, but not when proteins of the putative polyamine transport system are lost due to mutation. We propose that gonococci have a functional and sole polyamine transport system (PotFGHI) that specifically imports spermine and spermidine. Bioinformatics and molecular analyses showed that the transporter's potGHI genes are organized as an operon while the gene encoding the necessary cognate periplasmic polyamine-binding protein (PotF) is located elsewhere on the chromosome. Interestingly, within the potGHI locus, we identified a novel duplicated sequence, which we term the Pot-Gene-Associated-Duplication-Element, present in variable copy numbers in different gonococcal strains that was likely formed from the 5(') and 3(') ends of the coding sequences of the tandemly linked potH and potG genes, respectively.
authors.affiliation: Department of Microbiology and Immunology, Emory University School of Medicine, Atlanta 30322, GA, USA mgoytia@emory.edu.
authors.forename: Maira
authors.initials: M
authors.lastname: Goytia
authors.affiliation: Division of Biomedical Sciences, School of Medicine, University of California, Riverside, CA 92521, USA.
authors.forename: Leo
authors.initials: L
authors.lastname: Hawel
authors.affiliation: Department of Microbiology and Immunology, Emory University School of Medicine, Atlanta 30322, GA, USA.
authors.forename: Vijaya L
authors.initials: VL
authors.lastname: Dhulipala
authors.affiliation: Department of Medicine, Emory University School of Medicine, Atlanta, GA 30322, USA.
authors.forename: Sandeep J
authors.initials: SJ
authors.lastname: Joseph
authors.affiliation: Department of Medicine, Emory University School of Medicine, Atlanta, GA 30322, USA.
authors.forename: Timothy D
authors.initials: TD
authors.lastname: Read
authors.affiliation: Department of Microbiology and Immunology, Emory University School of Medicine, Atlanta 30322, GA, USA Laboratory of Bacterial Pathogenesis, Veterans Affairs Medical Center, Decatur, GA 30033, USA.
authors.forename: William M
authors.initials: WM
authors.lastname: Shafer
mesh_terms: D000595:Amino Acid Sequence; D001483:Base Sequence; D001692:Biological Transport; D019295:Computational Biology; D003470:Culture Media / Q000737:chemistry; D020440:Gene Duplication; D026901:Membrane Transport Proteins / Q000235:genetics / Q000378:metabolism; D008969:Molecular Sequence Data; D009154:Mutation; D009344:Neisseria gonorrhoeae / Q000235:genetics* / Q000254:growth & development / Q000378:metabolism; D009876:Operon; D013095:Spermidine / Q000378:metabolism*; D013096:Spermine / Q000378:metabolism*
chemical_list: D003470:Culture Media; D026901:Membrane Transport Proteins; D013096:Spermine; D013095:Spermidine
keywords: gene duplication; gonococci; polyamine transport