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Heterogeneity of the Yersinia YopM protein
A Boland1, S Havaux, G R Cornelis
1Microbial Pathogenesis Unit, Christian de Duve Institute of Cellular Pathology and Faculté de Médecine, Brussels, B-1200, Belgium.
Abstract:
Virulent Yersinia species (Y. pestis, Y. pseudotuberculosis and Y. enterocolitica) possess a 70 kb virulence plasmid that encodes the Yop virulon. This virulence system allows extracellular bacteria adhering at the surface of eukaryotic cells to secrete and inject bacterial effector proteins, called Yops, into the cytosol of these cells in order to disarm them. These secreted Yop proteins are remarkably conserved among the different species. A Y. enterocolitica O:8 strain was found to secrete a protein antigenically related to YopM but significantly larger. Sequencing of the corresponding gene showed that the protein was a YopM variant with three repeats of one domain. Comparison of the yopM gene of various Yersinia strains by PCR amplification, as well as analysis of the secreted Yop proteins by SDS-PAGE and Western blotting revealed that, unlike the other Yops, the YopM protein shows some heterogeneity.
Insights
Virulent Yersinia species use the Yop virulon to inject effector proteins (Yops) into host cells. A Yersinia enterocolitica strain exhibited a larger YopM variant, revealing heterogeneity in YopM proteins across Yersinia species.
Area of Science:
- Microbiology
- Molecular Biology
- Immunology
Background:
- Virulent Yersinia species (Y. pestis, Y. pseudotuberculosis, Y. enterocolitica) utilize a 70 kb virulence plasmid encoding the Yop virulon.
- The Yop virulon facilitates the secretion and injection of bacterial effector proteins (Yops) into eukaryotic cell cytosol to disarm host defenses.
- Yop proteins are generally conserved across different Yersinia species.
Purpose of the Study:
- To investigate the heterogeneity of Yop proteins, specifically YopM, among virulent Yersinia species.
- To characterize a larger YopM variant identified in a Yersinia enterocolitica O:8 strain.
Main Methods:
- PCR amplification of the yopM gene from various Yersinia strains.
- SDS-PAGE and Western blotting to analyze secreted Yop proteins.
- Gene sequencing to identify the structural basis of the YopM variant.
Main Results:
- A Yersinia enterocolitica O:8 strain secreted a YopM variant antigenically related but significantly larger than typical YopM.
- Sequencing revealed the YopM variant contained three tandem repeats of a specific domain.
- Analysis of yopM genes and secreted Yop proteins demonstrated heterogeneity in YopM, unlike other Yops.
Conclusions:
- YopM exhibits significant heterogeneity among Yersinia species, contrasting with the conserved nature of other Yops.
- The identified YopM variant with repeated domains contributes to this observed heterogeneity.
- Understanding YopM variability is crucial for comprehending Yersinia pathogenesis and host immune evasion strategies.