Impact of CodY protein on metabolism, sporulation and virulence in Clostridioides difficile ribotype 027

• Published in: PloS one 2019-01, Vol.14 (1), p.e0206896
• Main Authors: Daou, Nadine, Wang, Yuanguo, Levdikov, Vladimir M, Nandakumar, Madhumitha, Livny, Jonathan, Bouillaut, Laurent, Blagova, Elena, Zhang, Keshan, Belitsky, Boris R, Rhee, Kyu, Wilkinson, Anthony J, Sun, Xingmin, Sonenshein, Abraham L
• Format: Article
• Language: English
• Subjects: Amino Acid Sequence; Amino acids; Analysis; Animals; Antibiotics; Bacterial Proteins - chemistry; Bacterial Proteins - genetics; Bacterial Proteins - metabolism; Bacterial Toxins - toxicity; Binding proteins; Biology and Life Sciences; Biosynthetic Pathways - drug effects; Biosynthetic Pathways - genetics; Blood proteins; Cell survival; Clostridioides difficile - genetics; Clostridioides difficile - metabolism; Clostridioides difficile - pathogenicity; Clostridium difficile; CodY protein; Deactivation; Diarrhea - microbiology; Ethanolamine - metabolism; Gene expression; Gene Expression Regulation, Bacterial - drug effects; Genes; Genes, Bacterial; Genetic aspects; Genetic engineering; Health aspects; Inactivation; Infection; Infectious diseases; Laboratories; Medicine and Health Sciences; Metabolism; Metabolites; Mice, Inbred C57BL; Molecular biology; Motility; Multigene Family; Mutants; Operon - genetics; Physiological aspects; Point Mutation - genetics; Protein Domains; Protein turnover; Proteins; Recurrence (Disease); Recurrent infection; Ribotyping; RNA polymerase; Spores; Spores, Bacterial - genetics; Spores, Bacterial - physiology; Sporulation; Streptococcus infections; Toxins; Transcription, Genetic - drug effects; Veterinary colleges; Veterinary medicine; Virulence; Virulence (Microbiology); Virulence - genetics
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0206896

Toxin synthesis and endospore formation are two of the most critical factors that determine the outcome of infection by Clostridioides difficile. The two major toxins, TcdA and TcdB, are the principal factors causing damage to the host. Spores are the infectious form of C. difficile, permit survival of the bacterium during antibiotic treatment and are the predominant cell form that leads to recurrent infection. Toxin production and sporulation have their own specific mechanisms of regulation, but they share negative regulation by the global regulatory protein CodY. Determining the extent of such regulation and its detailed mechanism is important for understanding the linkage between two apparently independent biological phenomena and raises the possibility of creating new ways of limiting infection. The work described here shows that a codY null mutant of a hypervirulent (ribotype 027) strain is even more virulent than its parent in a mouse model of infection and that the mutant expresses most sporulation genes prematurely during exponential growth phase. Moreover, examining the expression patterns of mutants producing CodY proteins with different levels of residual activity revealed that expression of the toxin genes is dependent on total CodY inactivation, whereas most sporulation genes are turned on when CodY activity is only partially diminished. These results suggest that, in wild-type cells undergoing nutrient limitation, sporulation genes can be turned on before the toxin genes.