Regulation of virulence factors in Yersinia enterocolitica
Abstract This review describes how environmental stimuli can modulate the expression of virulence factors in Y. enterocolitica. The molecular mechanisms involved in regulation of virulence gene expression are crucial and depend (among others) on changes in DNA topology and the activity of transcriptional factors such as regulatory proteins of the AraC family, response regulators of the two-component regulatory systems and sigma factors. These systems affect the survival of Y enterocolitica in extra- and intracellular stress conditions. Growth temperature, osmolarity, pH, calcium and iron ions influence the expression of Y. enterocolitica virulence factors. Some characteristics of such virulence factors as LPS, enterotoxin Yst, adhesions Inv, Ail, YadA, Myf and their mechanism of regulation are described. Special focus is on the Yop virulon and the type III secretion system. Some new information regarding the regulation of Yops is presented.
1. Introduction. 2. The molecular mechanisms of adaptative responses. 2.1. Changes in opology of DNA. 2.1.1. DNA supercoiling. 2.1.2. Topology DNA influences expression of Y. enterocolitica genes. 2.2. Regulons of sigma factors. 2.3. Two-component regulatory systems. 3. Regulation of virulence factors of Y. enterocolitica in response to environmental signals. 3.1. The ability of free-living cells of Y. enterocolitica before invasion of the host. The early stages of infection connected with the movement of the pathogen into the host organism. 3.1.1. Lipopolysaccharide (LPS). 3.1.2. Enterotoxin Yst. 3.1.3. Iron acquisition by siderophore-dependent transport. 3.1.4. Maltose and the maltose regulon. 3.2. Virulence factors involved in the colonization and invasion of epithelial tissue. 3.2.1. Invasin Inv. 3.2.2. Adhesin Ail. 3.2.3. YadA protein. 3.2.4. Myf antigen. 3.3. Activity of the Yop virulon-extracellular growth of Y. enterocolitica and spread to deeper issues. 3.3.1. Virulon Yop. 3.3.2. Yop protein effectors. 3.3.3. Mechanism of the secretion and translocation
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