title: A single qrr gene is necessary and sufficient for LuxO-mediated regulation in Vibrio fischeri.
abstract: All members of the Vibrionaceae harbour LuxO, a response regulator that integrates outputs from various signalling systems, ultimately controlling specific traits that are crucial to the distinct biology of each species. LuxO is phosphorylated in response to low cell density, activating the transcription of a family of small RNAs called Qrrs, which in turn, control the levels of a global regulatory protein conserved within the Vibrionaceae. Although the function of each Qrr is similar, the number of qrr genes varies among the different species. Using a bioinformatics approach, we have determined the number of qrr genes in fully sequenced Vibrionaceae members. Phylogenetic analysis suggests the most recent common ancestor of all Vibrionaceae shared a single, ancestral qrr gene, which duplicated and diverged into multiple qrr genes in some present-day vibrio lineages. To demonstrate that a single qrr gene is sufficient to mediate repression of LitR, the global regulator in Vibrio fischeri, we have performed a series of genetic and phenotypic analyses of the LuxO pathway and its output. Our studies contribute to a better understanding of the ancestral state of these pathways in vibrios, as well as to the evolution and divergence of other sRNAs within different bacterial lineages.
authors.affiliation: Department of Medical Microbiology and Immunology, University of Wisconsin School of Medicine and Public Health, 1550 Linden Drive, Madison, WI 53706-1521, USA. miyashiro@wisc.edu
authors.forename: Tim
authors.initials: T
authors.lastname: Miyashiro
authors.forename: Michael S
authors.initials: MS
authors.lastname: Wollenberg
authors.forename: Xiaodan
authors.initials: X
authors.lastname: Cao
authors.forename: Dane
authors.initials: D
authors.lastname: Oehlert
authors.forename: Edward G
authors.initials: EG
authors.lastname: Ruby
mesh_terms: D048908:Aliivibrio fischeri / Q000235:genetics* / Q000378:metabolism; D000818:Animals; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D019295:Computational Biology; D017124:Conserved Sequence; D049832:Decapodiformes / Q000382:microbiology; D015964:Gene Expression Regulation, Bacterial; D005798:Genes, Bacterial; D049449:Luminescence; D010802:Phylogeny; D012097:Repressor Proteins / Q000235:genetics / Q000378:metabolism*; D017422:Sequence Analysis, DNA
chemical_list: D001426:Bacterial Proteins; D012097:Repressor Proteins