The mtr (multiple transferable resistance) system of Neisseria gonorrhoeae determines levels of gonococcal resistance to hydrophobic agents (HAs), including detergent-like fatty acids and bile salts that bathe certain mucosal surfaces. The genetic organization of the mtr system was determined and found to consist of the mtrR gene, which encodes a transcriptional regulator (MtrR), and three tandemly linked genes termed mtrCDE. The mtrCDE genes were organized in the same apparent transcriptional unit, upstream and divergent from the mtrR gene. The mtrCDE-encoded proteins of N. gonorrhoeae were analogous to a family of bacterial efflux/transport proteins, notably the MexABOprK proteins of Pseudomonas aeruginosa and the AcrAE and EnvCD proteins of Escherichia coli, that mediate resistance to drugs, dyes, and detergents. Inactivation of the mtrC gene resulted in loss of the MtrC lipoprotein and rendered gonococci hypersusceptible to structurally diverse HAs; this revealed the importance of the mtr system in determining HAR in gonococci. Further support for a role of the mtrCDE gene complex in determining levels of HAR in gonococci was evident when transformants bearing mutations in the mtrR gene were analysed. In this respect, missense and null mutations in the mtrR gene were found to result in increased levels of MtrC and HAR. However, high levels of MtrC and HAR, similar to those observed for clinical isolates, were associated with a single bp deletion in a 13 bp inverted repeat sequence that intervened the divergent mtrR and mtrC genes. We propose that the 13 bp inverted-repeat sequence represents a transcriptional control element that regulates expression of the mtrRCDE gene complex, thereby modulating levels of gonococcal susceptibility to HA.
BakerR. F.,
YanofskyC.1968; The periodicity of RNA polymerase initiations: a new regulatory feature of transcription. Proc Natl Acad Sci USA 60:313–320
BlakeM. S.,
JohnstonK. H.,
Russell-JonesG. J.,
GotschlichE. C.1984; A rapid, sensitive method for detection of alkaline phosphatase-conjugated anti-antibody on Western blots. Anal Biochem 136:175–179
BradfordM. M.1976; A rapid and sensitive method for the quantitation of microgram quantities of protein utilizing the principle of protein-dye binding. Anal Biochem 72:248–254
ChenC.-Y.,
ParsonsC. S.,
MorseS. A.1985 Membrane proteolipids of Neisseriagonorrhoeae
. In The Pathogenic Neisseriae pp 360–365 Edited by
SchoolnikG. K.
Washington, DC: American Society for Microbiology;
ClarkV. L.,
CampbellL. A.,
PalermoD. A.,
EvansT. M.,
KlimpelK. W.1987; Induction and repression of outer membrane proteins by anaerobic growth of Neisseria gonorrhoeae
. Infect Immun 55:1359–1364
CornelissenC. N.,
BiswasG. D.,
TsaiJ.,
ParuchuriD. K.,
ThompsonS.,
SparlingP. F.1992; Gonococcal transferrin-binding protein 1 is required for transferrin utilization and is homologous to TonB-dependent outer membrane receptors. J Bacteriol 174:5788–5797
DeMarco de HormaecheR.,
MehlertA.,
YoungD. B.,
de HormaecheC. E.1991 Antigenic homology between the 65 kDa heat shock protein of Mycobacterium tuberculosis, GroEL of E. coli and proteins of Neisseria gonorrhoeae expressed during infection. In Neisseriae 1990 pp 199–203 Edited by
AchtmanM.
and others Berlin: Walter de Gruyter;
DunbarB. S.,
MuraH.,
TimmonsT.1990; Protein analysis using high-resolution two dimensional polyacrylamide gel electro-phoresis. Methods Enzymol 186:441–459
GoodmanS. D.,
ScoccaJ. J.1988; Identification and arrangement of the DNA sequence recognized in specific transformation of Neisseria gonorrhoeae
. Proc Natl Acad Sci USA 85:6952–6986
GuthmillerJ. M.,
KraigE.,
CagleM. P.,
KolodrubetzD.1990; Sequence of the IktD gene from Actinobacillus actinomycetemcomitans
. Nucleic Acids Res 59:5992
HessJ.,
WeisW.,
VogelM.,
GoebelW.1986; Nucleotide sequence of a plasmid-encoded hemolysin determinant and its comparison with a chromosomal hemolysin sequence. FEMS Microbiol Lett 34:1–11
InnisM. A.,
TokunagaM.,
WilliamsM. E.,
LorangerJ. M.,
ChangS.-Y.,
ChangS.,
WuH. C.1984; Nucleotide sequence of the Escherichia coli pro lipoprotein signal peptidase (Isp) gene. Proc Natl Acad Sci USA 81:3708–3712
JuddR. C.,
StrangeJ. C.,
PettitR. K.,
ShaferW. M.1991;
Identification and characterization of a conserved outer-membrane protein of Neisseria gonorrhoeae
. Mol Microbiol 5:1091–1096
KleinJ. R.,
HenrichB. H.,
PlappR.1991; Molecular analysis and nucleotide sequence of the envCD operon of Escherichia coli
. Mol & Gen Genet 230:230–240
McAllisterC. F.,
StephensD. S.1993; Analysis in Neisseria meningitidis and other Neisseria species of genes homologous to the FKBP immunophilin family. Mol Microbiol 10:13–24
MorseS. A.,
LyskoP. G.,
McFarlandL.,
KnappJ. S.,
SandstromE.,
CritchlowC.,
HolmesK. K.1982; Gonococcal strains from homosexual men have outer membranes with reduced permeability to hydrophobic molecules. Infect Immun 37:432–438
NiesD.,
NiesA.,
ChuL.,
SilverS.1989; Expression and nucleotide sequence of a plasmid-determined divalent cation efflux system from Alcaligenes eutrophus
. Proc Natl Acad Sci USA 86:7351–7355
O’FarrellP. Z.,
GoodmanH. M.,
O’FarrellP. H.1977; High-resolution two-dimensional electrophoresis of basic as well as acidic proteins. Cell 12:1133–1142
PooleK.,
HeinrichsD. E.,
NeshatS.1993a; Cloning and sequence analysis of an EnvCD homologue in Pseudomonas aeruginosa : regulation by iron and possible involvement in the secretion of siderophore pyoverdine. Mol Microbiol 10:529–544
SarubbiF. A.,
SparlingP. F.,
BlackmanE.,
LewisE.1975; Loss of low-level antibiotic resistance in Neisseria gonorrhoeae due to env mutations. J Bacteriol 124:750–756
ShaferW. M.,
GuymonL. F.,
LindI.,
SparlingP. F.1984; Identification of an envelope mutation (env-10) resulting in increased antibiotic susceptibility and pyocin resistance in a clinical isolate of Neisseria gonorrhoeae
. Antimicrob Agents Chemother 25:767–769
SparlingP. F.,
SarubbiF. A.,
BlackmanE.1975; Inheritance of low-level resistance to penicillin, tetracycline, and chloramphenicol in Neisseria gonorrhoeae
. J Bacteriol 124:740–749
SparlingP. F.,
SoxT. E.,
MohammedW.,
GuymonL. F.1978 Antibiotic resistance in the gonococcus: diverse mechanisms of coping with a hostile environment. In Immunobiology of Neisseria gonorrhoeae pp 44–52 Edited by
BrooksG.
and others Washington, DC: American Society for Microbiology;
StarkovaZ.,
ThomasP.,
StarkaJ.1978; Morphological mutants of Escherichia coli: nature of the permeability in mon and envC cells. Ann Microbiol Inst Pasteur 129:265–284
SwansonJ.,
MayerL. W.,
TamM. R.1982; Antigenicity of Neisseria gonorrhoeae outer membrane protein(s) III detected by immunoprecipitation and Western blot transfer with a monoclonal antibody. Infect Immun 38:668–672
SwartzmanE.,
SilvermanM.,
MeighenE. A.1992; The luxR
gene product of Vibrio harveyi is a transcriptional activator of the lux promoter. J Bacteriol 17:7490–7493