Characterization of the sporulation initiation pathway of Clostridium difficile and its role in toxin production.
Clostridium difficile is responsible for significant mortality and morbidity in the hospitalized elderly. C. difficile spores are infectious and are a major factor contributing to nosocomial transmission. The Spo0A response regulator is the master regulator for sporulation initiation and can influence many other cellular processes. Using the ClosTron gene knockout system, we inactivated genes encoding Spo0A and a putative sporulation-associated sensor histidine kinase in C. difficile. Inactivation of spo0A resulted in an asporogeneous phenotype, whereas inactivation of the kinase reduced C. difficile sporulation capacity by 3.5-fold, suggesting that this kinase also has a role in sporulation initiation. Furthermore, inactivation of either spo0A or the kinase resulted in a marked defect in C. difficile toxin production. Therefore, Spo0A and the signaling pathway that modulates its activity appear to be involved in regulation of toxin synthesis in C. difficile. In addition, Spo0A was directly phosphorylated by a putative sporulation-associated kinase, supporting the hypothesis that sporulation initiation in C. difficile is controlled by a two-component signal transduction system rather than a multicomponent phosphorelay. The implications of these findings for C. difficile sporulation, virulence, and transmission are discussed.
Institute of Molecular and Cellular Biology, Faculty of Biological Sciences, Leeds University, Leeds, United Kingdom.
Sarah
S
Underwood
Shuang
S
Guan
Vinod
V
Vijayasubhash
Simon D
SD
Baines
Luke
L
Graham
Richard J
RJ
Lewis
Mark H
MH
Wilcox
Keith
K
Stephenson
D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D001427:Bacterial Toxins / Q000096:biosynthesis* / Q000235:genetics; D015153:Blotting, Western; D016360:Clostridioides difficile / Q000235:genetics / Q000254:growth & development* / Q000378:metabolism*; D019295:Computational Biology; D004591:Electrophoresis, Polyacrylamide Gel; D000071677:Histidine Kinase; D008969:Molecular Sequence Data; D010766:Phosphorylation; D011494:Protein Kinases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D017386:Sequence Homology, Amino Acid; D015398:Signal Transduction / Q000235:genetics / Q000502:physiology; D013171:Spores, Bacterial / Q000235:genetics / Q000254:growth & development*
D001426:Bacterial Proteins; D001427:Bacterial Toxins; D011494:Protein Kinases; D000071677:Histidine Kinase