Construction and Characterization of a
            <i>cheA</i>
            Mutant of
            <i>Treponema denticola</i>

Lux, Renate; Sim, Jee-Hyun; Tsai, Jon P.; Shi, Wenyuan

doi:10.1128/jb.184.11.3130-3134.2002

Cited by 26 publications

(34 citation statements)

References 47 publications

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“…Allelic replacement mutagenesis of two MCP encoding genes, dmcA and dmcB, resulted in a decreased chemotactic response to serum and albumin (Kataoka et al, 1997;Li et al, 1999). As expected, a cheA knockout mutant, which lacks the central kinase of the chemotaxis pathway, failed to respond chemotactically to serum (Lux et al, 2002).…”

Section: Chemotaxissupporting

confidence: 79%

Virulence Factors of the Oral Spirochete Treponema denticola

et al. 2010

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There is compelling evidence that treponemes are involved in the etiology of several chronic diseases, including chronic periodontitis as well as other forms of periodontal disease. There are interesting parallels with other chronic diseases caused by treponemes that may indicate similar virulence characteristics. Chronic periodontitis is a polymicrobial disease, and recent animal studies indicate that co-infection of Treponema denticola with other periodontal pathogens can enhance alveolar bone resorption. The bacterium has a suite of molecular determinants that could enable it to cause tissue damage and subvert the host immune response. In addition to this, it has several non-classic virulence determinants that enable it to interact with other pathogenic bacteria and the host in ways that are likely to promote disease progression. Recent advances, especially in molecular-based methodologies, have greatly improved our knowledge of this bacterium and its role in disease.

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Section: Chemotaxissupporting

confidence: 79%

Virulence Factors of the Oral Spirochete Treponema denticola

et al. 2010

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“…Because the treponemes have only one homolog of these genes in their genomes, these clusters also likely function in chemotaxis. In support of this proposition, analysis of a cheA mutant in T. denticola revealed it to be nonchemotactic (37 Reactions were stopped, and products were analyzed as described in the text. Phosphor images are shown in the left panels, and relative intensities (PI "volumes") are shown in the right panels.…”

Section: Discussionmentioning

confidence: 94%

CheY3 of Borrelia burgdorferi Is the Key Response Regulator Essential for Chemotaxis and Forms a Long-Lived Phosphorylated Intermediate

et al. 2011

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Spirochetes have a unique cell structure: These bacteria have internal periplasmic flagella subterminally attached at each cell end. How spirochetes coordinate the rotation of the periplasmic flagella for chemotaxis is poorly understood. In other bacteria, modulation of flagellar rotation is essential for chemotaxis, and phosphorylation-dephosphorylation of the response regulator CheY plays a key role in regulating this rotary motion. The genome of the Lyme disease spirochete Borrelia burgdorferi contains multiple homologues of chemotaxis genes, including three copies of cheY, referred to as cheY1, cheY2, and cheY3. To investigate the function of these genes, we targeted them separately or in combination by allelic exchange mutagenesis. Whereas wild-type cells ran, paused (flexed), and reversed, cells of all single, double, and triple mutants that contained an inactivated cheY3 gene constantly ran. Capillary tube chemotaxis assays indicated that only those strains with a mutation in cheY3 were deficient in chemotaxis, and cheY3 complementation restored chemotactic ability. In vitro phosphorylation assays indicated that CheY3 was more efficiently phosphorylated by CheA2 than by CheA1, and the CheY3-P intermediate generated was considerably more stable than the CheY-P proteins found in most other bacteria. The results point toward CheY3 being the key response regulator essential for chemotaxis in B. burgdorferi. In addition, the stability of CheY3-P may be critical for coordination of the rotation of the periplasmic flagella.Spirochetes are a group of motile bacteria that have a unique morphology and means of motility. On the surface of the spirochete is an outer membrane, which is often referred to as the outer membrane sheath. Within this outer membrane are the cell cylinder and the periplasmic flagella. The periplasmic flagella reside between the outer membrane and the cell cylinder. Because of its medical importance and recent advances in genetic manipulation, we have focused on the Lyme disease spirochete Borrelia burgdorferi to analyze spirochete motility and chemotaxis (for recent reviews, see references 10, 26, 34, and 68). This spirochete is relatively long (10 to 20 m) and thin (0.31 m) and has a flat-wave morphology, and motility is generated by rotation of the periplasmic flagella (11,14,24,25,33,42). Approximately 7 to 11 periplasmic flagella are subterminally attached at each cell end (30), and recent electron cryotomography analysis indicates that these periplasmic flagella form elegant ribbons that wrap clockwise (CW) around the cell cylinder (11). Not only are the periplasmic flagella involved in motility, but these organelles have a skeletal function that in part dictates the flat-wave shape of the cell (10,14,26,35,40,53,68). Thus, mutants that lack periplasmic flagella are nonmotile and have a rod-shaped morphology (35,40,53). Motility is accomplished by backward-moving flat waves along the cell body. These waves are generated by the coordinated rotation of the rigid periplasmic flagella as the...

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“…Our previous studies have shown that CheW 3 is essential for both chemotaxis and the polar clustering of the MCPs (28). The C terminus of CheW 3 contains a CheRlike domain, a combination that is found only in some spirochete species (28,55). It is likely that this unique domain architecture may require an additional partner, such as BB0569, to facilitate its physical interactions with the MCPs.…”

Section: Discussionmentioning

confidence: 99%

Hypothetical Protein BB0569 Is Essential for Chemotaxis of the Lyme Disease Spirochete Borrelia burgdorferi

Zhang

Li²,

Charon

et al. 2016

J Bacteriol

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The Lyme disease spirochete Borrelia burgdorferi has five putative methyl-accepting chemotaxis proteins (MCPs). In this report, we provide evidence that a hypothetical protein, BB0569, is essential for the chemotaxis of B. burgdorferi. While BB0569 lacks significant homology to the canonical MCPs, it contains a conserved domain (spanning residues 110 to 170) that is often evident in membrane-bound MCPs such as Tar and Tsr of Escherichia coli. Unlike Tar and Tsr, BB0569 lacks transmembrane regions and recognizable HAMP and methylation domains and is similar to TlpC, a cytoplasmic chemoreceptor of Rhodobacter sphaeroides. An isogenic mutant of BB0569 constantly runs in one direction and fails to respond to attractants, indicating that BB0569 is essential for chemotaxis. Immunofluorescence, green fluorescent protein (GFP) fusion, and cryo-electron tomography analyses demonstrate that BB0569 localizes at the cell poles and is required for chemoreceptor clustering at the cell poles. Protein cross-linking studies reveal that BB0569 forms large protein complexes with MCP3, indicative of its interactions with other MCPs. Interestingly, analysis of B. burgdorferi mcp mutants shows that inactivation of either mcp 2 or mcp 3 reduces the level of BB0569 substantially and that such a reduction is caused by protein turnover. Collectively, these results demonstrate that the domain composition and function of BB0569 are similar in some respects to those of TlpC but that these proteins are different in their cellular locations, further highlighting that the chemotaxis of B. burgdorferi is unique and different from the Escherichia coli and Salmonella enterica paradigm. IMPORTANCESpirochete chemotaxis differs substantially from the Escherichia coli and Salmonella enterica paradigm, and the basis for controlling the rotation of the bundles of periplasmic flagella at each end of the cell is unknown. In recent years, Borrelia burgdorferi, the causative agent of Lyme disease, has been used as a model organism to understand spirochete chemotaxis and its role in infectious processes of the disease. In this report, BB0569, a hypothetical protein of B. burgdorferi, has been investigated by using an approach of genetic, biochemistry, and cryo-electron tomography analyses. The results indicate that BB0569 has a distinct role in chemotaxis that may be unique to spirochetes and represents a novel paradigm. Chemotaxis allows bacteria to swim toward favorable environments or away from harmful ones by modulation of their swimming behavior (1, 2). The molecular mechanisms involved in bacterial chemotaxis have been extensively studied in two prototype organisms, Escherichia coli and Salmonella enterica (for recent reviews, see references 3-5). The chemotaxis signaling apparatus works as a supramolecular unit that is composed of three major components: methyl-accepting chemotaxis proteins (MCPs), the histidine kinase CheA, and the response regulator CheY (6, 7). MCPs sense various environmental and intracellular signals and control the acti...

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Construction and Characterization of a cheA Mutant of Treponema denticola

Cited by 26 publications

References 47 publications

Virulence Factors of the Oral Spirochete Treponema denticola

Virulence Factors of the Oral Spirochete Treponema denticola

CheY3 of Borrelia burgdorferi Is the Key Response Regulator Essential for Chemotaxis and Forms a Long-Lived Phosphorylated Intermediate

Hypothetical Protein BB0569 Is Essential for Chemotaxis of the Lyme Disease Spirochete Borrelia burgdorferi

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