Restoration of flagellar biosynthesis by varied mutational events in Campylobacter jejuni

Department of Microbiology, The University of Texas Southwestern Medical Center, Dallas, TX, USA.
Molecular Microbiology (Impact Factor: 5.03). 09/2008; 70(2):519-36. DOI: 10.1111/j.1365-2958.2008.06428.x
Source: PubMed

ABSTRACT Both a complex regulatory cascade involving the FlgSR two-component system and phase variation control expression of sigma(54)-dependent flagellar genes in Campylobacter jejuni. In this study, mutational mechanisms influencing production of the FlgS histidine kinase were discovered. Random non-motile, non-flagellated flgS variants were impaired for growth in the chick intestinal tract. Spontaneous revertants restored for flagellar biosynthesis, gene expression, and motility identified by in vivo and in vitro studies had undergone diverse intragenic and extragenic mutational events relative to flgS. Restorative intragenic events included true phase variation, second-site intragenic reversion, and insertion and deletion of short DNA segments within flgS. In vivo-isolated motile revertants possessed an identical, single extragenic mutation to create a partially constitutively active FlgR protein in the absence of FlgS. Considering that FlgR production is also influenced by phase variation, these new findings suggest that the FlgSR two-component system is unique in that each protein is controlled by phase variation and phosphorylation. In addition, this study highlights the mutational activities of C. jejuni and suggests that the bacterium may possess a repertoire of mutational mechanisms to overcome genetic lesions that impair production of virulence and colonization determinants while lacking a normal mismatch repair system.

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Available from: David Hendrixson, Aug 26, 2014
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    • "In support of this idea, others have observed that mutations in specific contingency genes affect the ability of C. jejuni to invade epithelial cells (in vitro) (Guerry et al., 2002), the antigenicity of specific cell-surface molecules (glycoproteins) associated with molecular mimicry both in vitro and in experimental human infection (Bernatchez et al., 2007; Linton et al., 2000; Guerry et al., 2002; Prendergast et al., 2004), and the colonization of chickens (Ashgar et al., 2007; Hendrixson, 2008). Several groups have also demonstrated that the C. jejuni genotype can affect colonization of the GI tract of poultry (Ahmed et al., 2002; Hook et al., 2005; Coward et al., 2008; Ridley et al., 2008) and that passage through poultry can affect both the genotype and colonization of poultry (Cawthraw et al., 1996; Wassenaar et al., 1998; Ringoir & Korolik, 2003; Jones et al., 2004; Kakuda & DiRita, 2006). "
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