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Updated: Jun 4, 2026

Quantifying Yersinia pseudotuberculosis Type III Secretion System Activity Following Iron Starvation and Anaerobic Growth
Published on: May 31, 2024
Cra negatively regulates acid survival in Yersinia pseudotuberculosis
Yangbo Hu1, Pei Lu, Yong Zhang
1State Key Laboratory of Virology, Wuhan Institute of Virology, The Chinese Academy of Sciences, Wuhan, Hubei Province, China.
Abstract:
Survival in acidic environments is important for successful infection of gastrointestinal pathogens. Many bacteria have evolved elaborate mechanisms by inducing or repressing gene expression, which subsequently provide pH homeostasis and enable acid survival. In this study, we employed comparative proteomic analysis to identify the acid-responsive proteins of a food-borne enteric bacterium, Yersinia pseudotuberculosis. The expression level of eight proteins involved in carbohydrate metabolism was up- or downregulated over twofold at pH 4.5 compared with pH 7.0. The role of a global transcriptional regulator catabolite repressor/activator Cra was further studied in this acid survival process. lacZ-fusion analysis showed that expression of cra was repressed under acidic pH. Deletion of the cra gene increased acid survival by 10-fold, whereas complementation restored the wild-type phenotype. These results lead us to propose that, in response to acidic pH, the expression of cra gene is downregulated to increase acid survival. This is the first study to demonstrate the regulatory role of Cra in acid survival in an enteric bacterium.
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