Analysis of the Roles of FlgP and FlgQ in Flagellar Motility of Campylobacter jejuni

Department of Microbiology, University of Texas Southwestern Medical Center, Dallas, TX 75390

^* To whom correspondence should be addressed. Email: david.hendrixson{at}utsouthwestern.edu.

	Abstract

Flagellar motility is an important determinant of Campylobacter jejuni required for promoting interactions with various hosts to promote gastroenteritis in humans or commensal colonization of many animals. In a previous study, we identified a non-motile mutant of C. jejuni 81-176 with a transposon insertion in cj1026c, but verification of the role of the encoded protein in motility was not determined. In this study, we have determined that cj1026c and the gene immediately downstream cj1025c (here annotated as flgP and flgQ, respectively) are both required for motility of C. jejuni but are not defective for flagellar biosynthesis. FlgP and FlgQ are not components of the transcriptional regulatory cascades to activate ²⁸- or ⁵⁴-dependent expression of flagellar genes. In addition, expression of flgP and flgQ are not largely dependent on ²⁸ or ⁵⁴. Immunblot analyses revealed that the majority of FlgP in C. jejuni is associated with the outer membrane. However, in the absence of FlgQ, the amounts of FlgP in the outer membrane of C. jejuni are greatly reduced, suggesting that FlgQ may be required for localization or stability of FlgP at this location. This study provides insight into features of FlgP and FlgQ, two proteins with previously undefined functions that are required for the larger, multi-component flagellar system of C. jejuni necessary for motility.