title: Identification, sequences, and expression of Treponema pallidum chemotaxis genes.
abstract: Treponema pallidum, the agent of syphilis, is a pathogenic spirochete that has no known mechanisms of genetic exchange and cannot be continuously cultivated in vitro. A probe based on the nucleotide sequence of the T. pallidum cheA gene was used to screen a T. pallidum genomic DNA library. A treponemal DNA region containing four open reading frames (orfs) was identified. The proteins encoded by these orfs have significant homology with proteins involved in bacterial chemotaxis. The orfs have been designated cheA, cheW, cheX, and cheY. The cheA, cheW, and cheY genes were individually-cloned and expressed in vitro. The observed molecular mass of each protein correlated well with its predicted molecular mass. Reverse transcriptase-PCR data indicate that cheA through cheY are co-transcribed. The organization of these genes suggests that they comprise an operon. We hypothesize that the ability to sense and respond to nutrient gradients is important for the survival and dissemination of T. pallidum in vivo. The presence of a putative che operon strongly suggests that T. pallidum has the potential for a chemotactic response.
authors.affiliation: Department of Epidemiology, School of Public Health, University of North Carolina, Chapel Hill 27599-7400, USA.
authors.forename: S R
authors.initials: SR
authors.lastname: Greene
authors.forename: L V
authors.initials: LV
authors.lastname: Stamm
authors.forename: J M
authors.initials: JM
authors.lastname: Hardham
authors.forename: N R
authors.initials: NR
authors.lastname: Young
authors.forename: J G
authors.initials: JG
authors.lastname: Frye
mesh_terms: D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000737:chemistry / Q000235:genetics*; D001483:Base Sequence; D002633:Chemotaxis / Q000235:genetics*; D003001:Cloning, Molecular; D004591:Electrophoresis, Polyacrylamide Gel; D015964:Gene Expression Regulation, Bacterial / Q000235:genetics*; D005798:Genes, Bacterial; D008565:Membrane Proteins / Q000737:chemistry / Q000235:genetics*; D000072236:Methyl-Accepting Chemotaxis Proteins; D008969:Molecular Sequence Data; D016366:Open Reading Frames / Q000235:genetics; D016133:Polymerase Chain Reaction; D015183:Restriction Mapping; D017422:Sequence Analysis, DNA; D017385:Sequence Homology; D017386:Sequence Homology, Amino Acid; D014210:Treponema pallidum / Q000737:chemistry / Q000235:genetics* / Q000502:physiology
chemical_list: D001426:Bacterial Proteins; C107800:CheX protein, Treponema pallidum; D008565:Membrane Proteins; D000072236:Methyl-Accepting Chemotaxis Proteins; C051236:CheW protein, Bacteria