ABSTRACT
Cj0859c, or FspA, is a small, acidic protein of Campylobacter jejuni that is expressed by a sigma(28) promoter. Analysis of the fspA gene in 41 isolates of C. jejuni revealed two overall variants of the predicted protein, FspA1 and FspA2. Secretion of FspA occurs in broth-grown bacteria and requires a minimum flagellar structure. The addition of recombinant FspA2, but not FspA1, to INT407 cells in vitro resulted in a rapid induction of apoptosis. These data define a novel C. jejuni virulence factor, and the observed heterogeneity among fspA alleles suggests alternate virulence potential among different strains.
Subject(s)
Bacterial Proteins/genetics , Campylobacter jejuni/physiology , Flagella/physiology , Polymorphism, Genetic , Virulence Factors/genetics , Amino Acid Sequence , Apoptosis , Bacterial Proteins/physiology , Campylobacter jejuni/genetics , Campylobacter jejuni/pathogenicity , Cell Line , Cluster Analysis , Flagella/chemistry , Humans , Molecular Sequence Data , Phylogeny , Promoter Regions, Genetic , Virulence Factors/physiologyABSTRACT
Analysis of the complete flagellin glycosylation locus of Campylobacter jejuni strain 81-176 revealed a less complex genomic organization than the corresponding region in the genome strain, C. jejuni NCTC 11168. Twenty-four of the 45 genes found between Cj1293 and Cj1337 in NCTC 11168 are missing in 81-176. Mutation of six new genes, in addition to three previously reported, resulted in a non-motile phenotype, consistent with a role in synthesis of pseudaminic acid (PseAc) or transfer of PseAc to flagellin. Mutation of Cj1316c or pseA had been shown to result in loss of the acetamidino form of pseudaminic acid (PseAm). Mutation of a second gene also resulted in loss of PseAm, as well as a minor modification that appears to be PseAm extended with N-acetyl-glutamic acid. Previously described mutants in C. jejuni 81-176 and Campylobacter coli VC167 that produced flagella lacking PseAm or PseAc failed to autoagglutinate. This suggests that interactions between modifications on adjacent flagella filaments are required for autoagglutination. Mutants (81-176) defective in autoagglutination showed a modest reduction in adherence and invasion of INT407 cells. However, there was a qualitative difference in binding patterns to INT407 cells using GFP-labelled 81-176 and mutants lacking PseAm. A mutant lacking PseAm was attenuated in the ferret diarrhoeal disease model.
Subject(s)
Campylobacter jejuni/genetics , Campylobacter jejuni/pathogenicity , Flagellin/metabolism , Genes, Bacterial/physiology , Agglutination , Base Sequence , Campylobacter jejuni/cytology , Cell Adhesion/genetics , DNA Mutational Analysis , Genome, Bacterial , Glycosylation , Intestinal Mucosa/microbiology , Molecular Sequence Data , Virulence/geneticsABSTRACT
A Campylobacter jejuni 81-176 mutant in Cj0977 was fully motile but reduced >3 logs compared to the parent in invasion of intestinal epithelial cells in vitro. The mutant was also attenuated in a ferret diarrheal disease model. Expression of Cj0977 protein was dependent on a minimal flagella structure.
Subject(s)
Bacterial Proteins/physiology , Campylobacter Infections/metabolism , Campylobacter jejuni/genetics , Sigma Factor/physiology , Animals , Bacterial Proteins/genetics , Bacterial Proteins/metabolism , Campylobacter jejuni/pathogenicity , Campylobacter jejuni/ultrastructure , Disease Models, Animal , Ferrets/microbiology , Mutation , Virulence/genetics , Virulence Factors/genetics , Virulence Factors/metabolismABSTRACT
Campylobacter jejuni 81-176 is capable of extensive replication within human monocytic cell vacuoles and induces apoptotic death via cytolethal distending toxin.
