The Myf fibrillae of Yersinia enterocolitica.

The Myf antigen produced by Yersinia enterocolitica appeared as a proteic polymer composed of 21 kDa subunits. By transposon mutagenesis we isolated Myf-defective mutants. Those allowed us to clone and sequence a 4.

YopB and YopD constitute a novel class of Yersinia Yop proteins.

Virulent Yersinia species harbor a common plasmid that encodes essential virulence determinants (Yersinia outer proteins [Yops]), which are regulated by the extracellular stimuli Ca2+ and temperature. The V-antigen-encoding operon has been shown to be involved in the Ca(2+)-regulated negative pathway. The genetic organization of the V-antigen operon and the sequence of the lcrGVH genes were recently presented.

Analysis of virC, an operon involved in the secretion of Yop proteins by Yersinia enterocolitica.

Upon incubation at 37 degrees C in the absence of Ca2+ ions, pathogenic yersiniae release large amounts of pYV plasmid-encoded proteins called Yops that are involved in pathogenesis. Yersinia enterocolitica also expresses an outer membrane protein that is considered an adhesin and called YadA (previously called P1 or YopA). The production of Yops is coordinately regulated by a 20-kb region of the plasmid referred to as the Ca2+ dependence region and containing at least four loci called virA, virB, virC, and virF.

ymoA, a Yersinia enterocolitica chromosomal gene modulating the expression of virulence functions.

The virulence functions of Yersinia enterocolitica include the pYV-encoded Yop proteins and YadA adhesin as well as the chromosome-encoded enterotoxin, Yst. The yop and yadA genes form a temperature-activated regulon controlled by the transcriptional activator VirF. Gene virF, also localized on pYV, is itself thermoinduced in the absence of other pYV genes.

Structural and functional similarities between the replication region of the Yersinia virulence plasmid and the RepFIIA replicons.

We sequenced the minimum replication region of the virulence plasmid pYVe439-80 from a serogroup O:9 Yersinia enterocolitica. This sequence is 68% homologous on a 1,873-nucleotide stretch to the sequence of the RepFIIA replicon of the resistance plasmid R100. The sequence contains two open reading frames, repA and repB, encoding proteins of 33,478 and 9,568 daltons, respectively.