title: Evolutionary history and functional characterization of three large genes involved in sporulation in Bacillus cereus group bacteria.
abstract: The Bacillus cereus group of bacteria is a group of closely related species that are of medical and economic relevance, including B. anthracis, B. cereus, and B. thuringiensis. Bacteria from the Bacillus cereus group encode three large, highly conserved genes of unknown function (named crdA, crdB, and crdC) that are composed of 16 to 35 copies of a repeated domain of 132 amino acids at the protein level. Bioinformatic analysis revealed that there is a phylogenetic bias in the genomic distribution of these genes and that strains harboring all three large genes mainly belong to cluster III of the B. cereus group phylogenetic tree. The evolutionary history of the three large genes implicates gain, loss, duplication, internal deletion, and lateral transfer. Furthermore, we show that the transcription of previously identified antisense open reading frames in crdB is simultaneously regulated with its host gene throughout the life cycle in vitro, with the highest expression being at the onset of sporulation. In B. anthracis, different combinations of double- and triple-knockout mutants of the three large genes displayed slower and less efficient sporulation processes than the parental strain. Altogether, the functional studies suggest an involvement of these three large genes in the sporulation process.
authors.affiliation: Laboratory for Microbial Dynamics, Department of Pharmaceutical Biosciences, School of Pharmacy, University of Oslo, P.O. Box 1068 Blindern, 0316 Oslo, Norway.
authors.forename: Lillian
authors.initials: L
authors.lastname: Reiter
authors.forename: Nicolas J
authors.initials: NJ
authors.lastname: Tourasse
authors.forename: Agnès
authors.initials: A
authors.lastname: Fouet
authors.forename: Raphaël
authors.initials: R
authors.lastname: Loll
authors.forename: Sophie
authors.initials: S
authors.lastname: Davison
authors.forename: Ole Andreas
authors.initials: OA
authors.lastname: Økstad
authors.forename: Armin P
authors.initials: AP
authors.lastname: Piehler
authors.forename: Anne-Brit
authors.initials: AB
authors.lastname: Kolstø
mesh_terms: D001409:Bacillus cereus / Q000235:genetics* / Q000502:physiology; D001426:Bacterial Proteins / Q000145:classification / Q000235:genetics*; D019295:Computational Biology; D019143:Evolution, Molecular; D010802:Phylogeny; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013171:Spores, Bacterial / Q000235:genetics* / Q000502:physiology
chemical_list: D001426:Bacterial Proteins