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Pleiotropic roles of Clostridium difficile sin locus

Authors :: Junjun Ou
Revathi Govind
Bruno Dupuy
Brintha Parasumanna Girinathan
Division of Biology [Kansas State University]
Kansas State University
Department of Agronomy [Kansas State University]
Pathogénèse des Bactéries Anaérobies / Pathogenesis of Bacterial Anaerobes (PBA (U-Pasteur_6))
Institut Pasteur [Paris]-Université Paris Diderot - Paris 7 (UPD7)
RG is supported by 1R15AI122173 from NIAID. Funds from the Johnson Cancer Center-KSU and a pilot project to RG from CBID-KU (1P20GM113117-01) also supported this work. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.
We thank following investigators for sharing their lab resources: David Ho, Rockefeller University, for FliC antibody
Wiep Klass, Leids University and Aimee Shen, Tufts University for Spo0A antibody
Linc Sonenshein, Tufts University for CodY antibody and UK::codY mutant
Nigel Minton, University of Nottingham, for the plasmid pMTL007C-E5
Robert Fagan for the vector pRPF185. We thank Jose E. Lopez for technical assistance throughout the study and Yusuf Ceftci, Varun Govind for editing the manuscript.
Institut Pasteur [Paris] (IP)-Université Paris Diderot - Paris 7 (UPD7)
Source :: PLoS Pathogens, Vol 14, Iss 3, p e1006940 (2018), PLoS Pathogens, PLoS Pathogens, Public Library of Science, 2018, 14 (3), pp.e1006940. ⟨10.1371/journal.ppat.1006940⟩, PLoS Pathogens, 2018, 14 (3), pp.e1006940. ⟨10.1371/journal.ppat.1006940⟩
Publication Year :: 2018
Publisher :: Public Library of Science (PLoS), 2018.
Abstract: Clostridium difficile is the primary cause of nosocomial diarrhea and pseudomembranous colitis. It produces dormant spores, which serve as an infectious vehicle responsible for transmission of the disease and persistence of the organism in the environment. In Bacillus subtilis, the sin locus coding SinR (113 aa) and SinI (57 aa) is responsible for sporulation inhibition. In B. subtilis, SinR mainly acts as a repressor of its target genes to control sporulation, biofilm formation, and autolysis. SinI is an inhibitor of SinR, so their interaction determines whether SinR can inhibit its target gene expression. The C. difficile genome carries two sinR homologs in the operon that we named sinR and sinR’, coding for SinR (112 aa) and SinR’ (105 aa), respectively. In this study, we constructed and characterized sin locus mutants in two different C. difficile strains R20291 and JIR8094, to decipher the locus’s role in C. difficile physiology. Transcriptome analysis of the sinRR’ mutants revealed their pleiotropic roles in controlling several pathways including sporulation, toxin production, and motility in C. difficile. Through various genetic and biochemical experiments, we have shown that SinR can regulate transcription of key regulators in these pathways, which includes sigD, spo0A, and codY. We have found that SinR’ acts as an antagonist to SinR by blocking its repressor activity. Using a hamster model, we have also demonstrated that the sin locus is needed for successful C. difficile infection. This study reveals the sin locus as a central link that connects the gene regulatory networks of sporulation, toxin production, and motility; three key pathways that are important for C. difficile pathogenesis.<br />Author summary In Bacillus subtilis, sporulation, competence and biofilm formation are regulated by a pleiotropic regulator called SinR. Two sinR homologs are present in C. difficile genome as an operon and henceforth labeled as sinR and sinR’. Our detailed investigation revealed that in C. difficile, the SinR and SinR’ are key master regulators needed for the regulation of several pathways including sporulation, toxin production, and motility.