title: Evolution and some functions of the NprR-NprRB quorum-sensing system in the Bacillus cereus group.
abstract: Quorum-sensing (QS) is a bacterial mechanism for regulation of gene expression in response to cell density. In Gram-positive bacteria, oligopeptides are the signaling molecules to elicit QS. The RNPP protein family (Rap, NprR, PlcR, and PrgX) are intracellular QS receptors that bind directly to their specific signaling peptide for regulating the transcription of several genes. NprR is the activator of a neutral protease in Bacillus subtilis, and it has been recently related to sporulation, cry genes transcription and extracellular protease activity in strains from the B. cereus group. In the B. thuringiensis genome, downstream nprR, a gene encoding a putative QS signaling propeptide (nprRB) was found. We hypothesized that the nprR and nprRB co-evolved because of their coordinated function in the B. cereus group. A phylogenetic tree of nucleotide sequences of nprR revealed six pherotypes, each corresponding to one putative mature NprRB sequence. The nprR tree does not match the current taxonomic grouping of the B. cereus group or the phylogenetic arrangement obtained when using MLST markers from the same strains. SKPDI and other synthetic peptides encoded in the nprRB gene from B. thuringiensis serovar thuringiensis strain 8741 had effect on temporal regulation of sporulation and expression of a cry1Aa'Z transcriptional fusion, but those peptides that stimulated earlier detection of spores decreased cry1Aa expression suggesting that NprR may either activate or repress the transcription of different genes.
authors.affiliation: Centro de Investigación en Alimentación y Desarrollo, A. C. Carretera a La Victoria Km 0.6, Hermosillo, Sonora, Mexico.
authors.forename: Jorge
authors.initials: J
authors.lastname: Rocha
authors.forename: Victor
authors.initials: V
authors.lastname: Flores
authors.forename: Rosina
authors.initials: R
authors.lastname: Cabrera
authors.forename: Adriana
authors.initials: A
authors.lastname: Soto-Guzmán
authors.forename: Giovana
authors.initials: G
authors.lastname: Granados
authors.forename: Eusebio
authors.initials: E
authors.lastname: Juaristi
authors.forename: Gabriel
authors.initials: G
authors.lastname: Guarneros
authors.forename: Mayra
authors.initials: M
authors.lastname: de la Torre
mesh_terms: D001409:Bacillus cereus / Q000235:genetics / Q000502:physiology*; D001412:Bacillus subtilis / Q000235:genetics / Q000502:physiology*; D001413:Bacillus thuringiensis / Q000235:genetics / Q000502:physiology*; D001426:Bacterial Proteins / Q000235:genetics* / Q000378:metabolism; D001427:Bacterial Toxins / Q000378:metabolism; D016000:Cluster Analysis; D004269:DNA, Bacterial / Q000737:chemistry / Q000235:genetics; D019143:Evolution, Molecular; D015964:Gene Expression Regulation, Bacterial; D053858:Metabolic Networks and Pathways / Q000235:genetics*; D008969:Molecular Sequence Data; D010802:Phylogeny; D053038:Quorum Sensing; D017422:Sequence Analysis, DNA; D017385:Sequence Homology; D013171:Spores, Bacterial / Q000254:growth & development
chemical_list: D001426:Bacterial Proteins; D001427:Bacterial Toxins; D004269:DNA, Bacterial