title: A cell-cell communication system regulates protease production during sporulation in bacteria of the Bacillus cereus group.
abstract: In sporulating Bacillus, major processes like virulence gene expression and sporulation are regulated by communication systems involving signalling peptides and regulators of the RNPP family. We investigated the role of one such regulator, NprR, in bacteria of the Bacillus cereus group. We show that NprR is a transcriptional regulator whose activity depends on the NprX signalling peptide. In association with NprX, NprR activates the transcription of an extracellular protease gene (nprA) during the first stage of the sporulation process. The transcription start site of the nprA gene has been identified and the minimal region necessary for full activation has been characterized by promoter mutagenesis. We demonstrate that the NprX peptide is secreted, processed and then reimported within the bacterial cell. Once inside the cell, the mature form of NprX, presumably the SKPDIVG heptapeptide, directly binds to NprR allowing nprA transcription. Alignment of available NprR sequences from different species of the B. cereus group defines seven NprR clusters associated with seven NprX heptapeptide classes. This cell-cell communication system was found to be strain-specific with a possible cross-talk between some pherotypes. The phylogenic relationship between NprR and NprX suggests a coevolution of the regulatory protein and its signalling peptide.
authors.affiliation: INRA, UMR 1319 - Micalis, La Minière, 78280 Guyancourt, France.
authors.forename: Stéphane
authors.initials: S
authors.lastname: Perchat
authors.forename: Thomas
authors.initials: T
authors.lastname: Dubois
authors.forename: Samira
authors.initials: S
authors.lastname: Zouhir
authors.forename: Myriam
authors.initials: M
authors.lastname: Gominet
authors.forename: Sandrine
authors.initials: S
authors.lastname: Poncet
authors.forename: Christelle
authors.initials: C
authors.lastname: Lemy
authors.forename: Magali
authors.initials: M
authors.lastname: Aumont-Nicaise
authors.forename: Josef
authors.initials: J
authors.lastname: Deutscher
authors.forename: Michel
authors.initials: M
authors.lastname: Gohar
authors.forename: Sylvie
authors.initials: S
authors.lastname: Nessler
authors.forename: Didier
authors.initials: D
authors.lastname: Lereclus
mesh_terms: D001409:Bacillus cereus / Q000201:enzymology / Q000502:physiology*; D001426:Bacterial Proteins / Q000096:biosynthesis*; D001483:Base Sequence; D004252:DNA Mutational Analysis; D015964:Gene Expression Regulation, Bacterial; D056265:Microbial Interactions; D008969:Molecular Sequence Data; D016296:Mutagenesis; D010447:Peptide Hydrolases / Q000096:biosynthesis*; D010802:Phylogeny; D011401:Promoter Regions, Genetic; D017386:Sequence Homology, Amino Acid; D015398:Signal Transduction; D013171:Spores, Bacterial / Q000254:growth & development*; D014157:Transcription Factors / Q000378:metabolism*; D024363:Transcription Initiation Site
chemical_list: D001426:Bacterial Proteins; D014157:Transcription Factors; D010447:Peptide Hydrolases