Phenotypic characterization of a virulence-associated protein, VagH, of Yersinia pseudotuberculosis reveals a tight link between VagH and the type III secretion system
| Autor: | Richard W. Titball, Martina Olofsson, Manoj Kumar Srivastava, Ann-Catrin Björnfot, Victoria L. Robinson, Sara Garbom, Hans Wolf-Watz, Petra C. F. Oyston |
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| Rok vydání: | 2007 |
| Předmět: |
Proteome
Virulence Factors Mutant Colony Count Microbial Virulence Yersinia pseudotuberculosis Infections Biology medicine.disease_cause Microbiology Type three secretion system Mice Bacterial Proteins medicine Yersinia pseudotuberculosis Animals Secretion Protein Methyltransferases RNA Messenger Escherichia coli Gene Oligonucleotide Array Sequence Analysis Escherichia coli Proteins Gene Expression Profiling Macrophages Methyltransferases biology.organism_classification Phenotype Cell biology Mice Inbred C57BL Disease Models Animal Protein Transport RNA Bacterial Female Gene Deletion Peptide Termination Factors |
| Zdroj: | Microbiology (Reading, England). 153(Pt 5) |
| ISSN: | 1350-0872 |
| Popis: | Recently, a number of attenuated mutants of Yersinia pseudotuberculosis have been identified using a bioinformatics approach. One of the target genes identified in that study was vagH, which the authors now characterized further. VagH shows homology to HemK of Escherichia coli, possessing methyltransferase activity similar to that of HemK, and targeting release factors 1 and 2. Microarray studies comparing the wild-type and the vagH mutant revealed that the mRNA levels of only a few genes were altered in the mutant. By proteome analysis, expression of the virulence determinant YopD was found to be increased, indicating a possible connection between VagH and the virulence plasmid-encoded type III secretion system (T3SS). Further analysis showed that Yop expression and secretion were repressed in a vagH mutant. This phenotype could be suppressed by trans-complementation with the wild-type vagH gene or by deletion of the negative regulator yopD. Also, in a similar manner to a T3SS-negative mutant, the avirulent vagH mutant was rapidly cleared from Peyer's patches and could not reach the spleen after oral infection of mice. In a manner analogous to that of T3SS mutants, the vagH mutant could not block phagocytosis by macrophages. However, a vagH mutant showed no defects in the T3SS-independent ability to proliferate intracellularly and replicated to levels similar to those of the wild-type in macrophages. In conclusion, the vagH mutant exhibits a virulence phenotype similar to that of a T3SS-negative mutant, indicating a tight link between VagH and type III secretion in Y. pseudotuberculosis. |
| Databáze: | OpenAIRE |
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