Borrelia burgdorferi CheY2 Is Dispensable for Chemotaxis or Motility but Crucial for the Infectious Life Cycle of the Spirochete

Abstract

The requirements for bacterial chemotaxis and motility range from dispensable to crucial for host colonization. Even though more than 50% of all sequenced prokaryotic genomes possess at least one chemotaxis signaling system, many of those genomes contain multiple copies of a chemotaxis gene. However, the functions of most of those additional genes are unknown. Most motile bacteria possess at least one CheY response regulator that is typically dedicated to the control of motility and which is usually essential for virulence. Borrelia burgdorferi appears to be notably different, in that it has three cheY genes, and our current studies on cheY2 suggests that it has varied effects on different aspects of the natural infection cycle. Mutants deficient in this protein exhibit normal motility and chemotaxis in vitro but show reduced virulence in mice. Specifically, the cheY2 mutants were severely attenuated in murine infection and dissemination to distant tissues after needle inoculation. Moreover, while ΔcheY2 spirochetes are able to survive normally in the Ixodes ticks, mice fed upon by the ΔcheY2-infected ticks did not develop a persistent infection in the murine host. Our data suggest that CheY2, despite resembling a typical response regulator, functions distinctively from most other chemotaxis CheY proteins. We propose that CheY2 serves as a regulator for a B. burgdorferi virulence determinant that is required for productive infection within vertebrate, but not tick, hosts.

BB0326 is responsible for the formation of periplasmic flagellar collar and assembly of the stator complex in Borrelia burgdorferi

“…The resistant clones were analyzed by PCR using appropriate primers. (Novak et al, 2016;Pitzer et al, 2011;Sultan et al, 2011;Sultan, Pitzer, Miller, & Motaleb, 2010;Xu et al, 2017). The result of relative quantification of the copies of bb0327 or bb0325 was normalized to 10 5 copies of enolase gene in each strain.…”

A tetratricopeptide repeat domain protein has profound effects on assembly of periplasmic flagella, morphology and motility of the lyme disease spirochete Borrelia burgdorferi

“…Growing B. burgdorferi clones were imaged using a Zeiss Imager M1 dark-field microscope connected to a digital camera to determine bacterial morphology (and motility). To determine B. burgdorferi motility, we performed swarm plate assays (Moon et al, 2016a;2016b;Xu et al, 2017). Briefly, approximately 1 × 10 8 cells in a 5 µl volume were spotted into 0.35% agarose plates containing BSK medium diluted in 1:10 in Dulbecco's phosphate-buffered saline.…”

“…Borrelia burgdorferi is the causative agent of Lyme disease, which is the most common vector-borne illness in the United States and Europe (Mead, 2015). Flagella-driven motility and chemotaxis are reported to be crucial for the pathogenesis of many bacteria including the spirochetes (Butler and Camilli, 2005;Li et al, 2010;Lertsethtakarn et al, 2011;Lambert et al, 2012;Sze et al, 2012;Guyard et al, 2013;Sultan et al, 2011;Lin et al, 2015;Motaleb et al, 2015;Sultan et al, 2015;Novak et al, 2016;Wunder et al, 2016;Moon et al, 2016a;Xu et al, 2017). Unlike other externally flagellated bacteria, spirochetes' flagella are located between the outer membrane and peptidoglycan layer i.e.…”

Borrelia burgdorferi Keeps Moving and Carries on: A Review of Borrelial Dissemination and Invasion

“…CheR and CheB are potential methyltransferase and methylesterase proteins, respectively, which may modify MCP. Modification of Xu et al ( 54 ).…”