title: A Recombination Directionality Factor Controls the Cell Type-Specific Activation of σK and the Fidelity of Spore Development in Clostridium difficile.
abstract: The strict anaerobe Clostridium difficile is the most common cause of nosocomial diarrhea, and the oxygen-resistant spores that it forms have a central role in the infectious cycle. The late stages of sporulation require the mother cell regulatory protein σK. In Bacillus subtilis, the onset of σK activity requires both excision of a prophage-like element (skinBs) inserted in the sigK gene and proteolytical removal of an inhibitory pro-sequence. Importantly, the rearrangement is restricted to the mother cell because the skinBs recombinase is produced specifically in this cell. In C. difficile, σK lacks a pro-sequence but a skinCd element is present. The product of the skinCd gene CD1231 shares similarity with large serine recombinases. We show that CD1231 is necessary for sporulation and skinCd excision. However, contrary to B. subtilis, expression of CD1231 is observed in vegetative cells and in both sporangial compartments. Nevertheless, we show that skinCd excision is under the control of mother cell regulatory proteins σE and SpoIIID. We then demonstrate that σE and SpoIIID control the expression of the skinCd gene CD1234, and that this gene is required for sporulation and skinCd excision. CD1231 and CD1234 appear to interact and both proteins are required for skinCd excision while only CD1231 is necessary for skinCd integration. Thus, CD1234 is a recombination directionality factor that delays and restricts skinCd excision to the terminal mother cell. Finally, while the skinCd element is not essential for sporulation, deletion of skinCd results in premature activity of σK and in spores with altered surface layers. Thus, skinCd excision is a key element controlling the onset of σK activity and the fidelity of spore development.
authors.affiliation: Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Oeiras, Portugal.
authors.forename: Mónica
authors.initials: M
authors.lastname: Serrano
authors.affiliation: Laboratoire Pathogénese des Bactéries Anaérobies, Institut Pasteur, Paris, France.|University Paris Diderot, Sorbonne Paris Cité, Paris, France.
authors.forename: Nicolas
authors.initials: N
authors.lastname: Kint
authors.affiliation: Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Oeiras, Portugal.
authors.forename: Fátima C
authors.initials: FC
authors.lastname: Pereira
authors.affiliation: Laboratoire Pathogénese des Bactéries Anaérobies, Institut Pasteur, Paris, France.|University Paris Diderot, Sorbonne Paris Cité, Paris, France.
authors.forename: Laure
authors.initials: L
authors.lastname: Saujet
authors.affiliation: Laboratoire Pathogénese des Bactéries Anaérobies, Institut Pasteur, Paris, France.|University Paris Diderot, Sorbonne Paris Cité, Paris, France.
authors.forename: Pierre
authors.initials: P
authors.lastname: Boudry
authors.affiliation: Laboratoire Pathogénese des Bactéries Anaérobies, Institut Pasteur, Paris, France.|University Paris Diderot, Sorbonne Paris Cité, Paris, France.
authors.forename: Bruno
authors.initials: B
authors.lastname: Dupuy
authors.affiliation: Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Oeiras, Portugal.
authors.forename: Adriano O
authors.identifier: 0000-0003-4292-4802
authors.initials: AO
authors.lastname: Henriques
authors.affiliation: Laboratoire Pathogénese des Bactéries Anaérobies, Institut Pasteur, Paris, France.|University Paris Diderot, Sorbonne Paris Cité, Paris, France.
authors.forename: Isabelle
authors.initials: I
authors.lastname: Martin-Verstraete
mesh_terms: D001412:Bacillus subtilis / Q000235:genetics; D002453:Cell Cycle / Q000235:genetics; D016360:Clostridioides difficile / Q000235:genetics* / Q000472:pathogenicity; D003428:Cross Infection / Q000235:genetics / Q000382:microbiology; D003967:Diarrhea / Q000235:genetics* / Q000382:microbiology; D015964:Gene Expression Regulation, Bacterial; D006801:Humans; D010100:Oxygen / Q000378:metabolism; D039002:Prophages / Q000235:genetics; D011995:Recombination, Genetic; D012808:Sigma Factor / Q000235:genetics*; D013171:Spores, Bacterial / Q000235:genetics* / Q000254:growth & development
chemical_list: D012808:Sigma Factor; D010100:Oxygen