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CapA, an Autotransporter Protein of Campylobacter jejuni, Mediates Association with Human Epithelial Cells and Colonization of the Chicken Gut

Ashgar, Sami S.A.; Oldfield, Neil J.; Wooldridge, Karl G.; Jones, Michael A.; Irving, Greg J.; Turner, David P.J.; Ala'Aldeen, Dlawer A.A.

Authors

Sami S.A. Ashgar

Greg J. Irving

DAVID TURNER david.turner@nottingham.ac.uk
Clinical Associate Professor

Dlawer A.A. Ala'Aldeen



Abstract

Two putative autotransporter proteins, CapA and CapB, were identified in silico from the genome sequence of Campylobacter jejuni NCTC11168. The genes encoding each protein contain homopolymeric tracts, suggestive of phase variation mediated by a slipped-strand mispairing mechanism; in each case the gene sequence contained frameshifts at these positions. The C-terminal two-thirds of the two genes, as well as a portion of the predicted signal peptides, were identical; the remaining N-terminal portions were gene specific. Both genes were cloned and expressed; recombinant polypeptides were purified and used to raise rabbit polyclonal monospeciflc antisera. Using immunoblotting, expression of the ca.116-kBa CapA protein was demonstrated for in vitro-grown cells of strain NCTC11168, for 4 out of 11 recent human fecal isolates, and for 2 out of 8 sequence-typed strains examined. Expression of CapB was not detected for any of the strains tested. Surface localization of CapA was demonstrated by subcellular fractionation and immunogold electron microscopy. Export of CapA was inhibited by globomycin, reinforcing the bioinformatic prediction that the protein is a lipoprotein. A capA insertion mutant had a significantly reduced capacity for association with and invasion of Caco-2 cells and failed to colonize and persist in chickens, indicating that CapA plays a role in host association and colonization by Campylobacter. In view of this demonstrated role, we propose that CapA stands for Campylobacter adhesion protein A.

Citation

Ashgar, S. S., Oldfield, N. J., Wooldridge, K. G., Jones, M. A., Irving, G. J., Turner, D. P., & Ala'Aldeen, D. A. (2007). CapA, an Autotransporter Protein of Campylobacter jejuni, Mediates Association with Human Epithelial Cells and Colonization of the Chicken Gut. Journal of Bacteriology, 189(5), 1856-1865. https://doi.org/10.1128/JB.01427-06

Journal Article Type Article
Acceptance Date Dec 8, 2006
Online Publication Date Mar 1, 2007
Publication Date Mar 1, 2007
Deposit Date Aug 2, 2022
Journal Journal of Bacteriology
Print ISSN 0021-9193
Electronic ISSN 1098-5530
Publisher American Society for Microbiology
Peer Reviewed Peer Reviewed
Volume 189
Issue 5
Pages 1856-1865
DOI https://doi.org/10.1128/JB.01427-06
Public URL https://nottingham-repository.worktribe.com/output/3129926
Publisher URL https://journals.asm.org/doi/10.1128/JB.01427-06