title: Identification of a novel prophage regulator in Escherichia coli controlling the expression of type III secretion.
abstract: This study has identified horizontally acquired genomic regions of enterohaemorrhagic Escherichia coli O157:H7 that regulate expression of the type III secretion (T3S) system encoded by the locus of enterocyte effacement (LEE). Deletion of O-island 51, a 14.93 kb cryptic prophage (CP-933C), resulted in a reduction in LEE expression and T3S. The deletion also had a reduced capacity to attach to epithelial cells and significantly reduced E. coli O157 excretion levels from sheep. Further characterization of O-island 51 identified a novel positive regulator of the LEE, encoded by ecs1581 in the E. coli O157:H7 strain Sakai genome and present but not annotated in the E. coli strain EDL933 sequence. Functionally important residues of ECs1581 were identified based on phenotypic variants present in sequenced E. coli strains and the regulator was termed RgdR based on a motif demonstrated to be important for stimulation of gene expression. While RgdR activated expression from the LEE1 promoter in the presence or absence of the LEE-encoded regulator (Ler), RgdR stimulation of T3S required ler and Ler autoregulation. RgdR also controlled the expression of other phenotypes, including motility, indicating that this new family of regulators may have a more global role in E. coli gene expression.
authors: Immunity and Infection Division, The Roslin Institute and R(D)SVS, University of Edinburgh, Edinburgh EH25 9RG, UK.
authors: Allen F
authors: AF
authors: Flockhart
authors: Jai J
authors: JJ
authors: Tree
authors: Xuefang
authors: X
authors: Xu
authors: Maryia
authors: M
authors: Karpiyevich
authors: Sean P
authors: SP
authors: McAteer
authors: Ronen
authors: R
authors: Rosenblum
authors: Darren J
authors: DJ
authors: Shaw
authors: Christopher J
authors: CJ
authors: Low
authors: Angus
authors: A
authors: Best
authors: Victor
authors: V
authors: Gannon
authors: Chad
authors: C
authors: Laing
authors: Kenan C
authors: KC
authors: Murphy
authors: John M
authors: JM
authors: Leong
authors: Thamarai
authors: T
authors: Schneiders
authors: Roberto
authors: R
authors: La Ragione
authors: David L
authors: DL
authors: Gally
mesh_terms: D000818:Animals; D058947:Bacterial Secretion Systems; D004927:Escherichia coli Infections / Q000382:microbiology*; D019453:Escherichia coli O157 / Q000235:genetics / Q000378:metabolism / Q000821:virology*; D029968:Escherichia coli Proteins / Q000235:genetics / Q000378:metabolism; D017353:Gene Deletion; D015964:Gene Expression Regulation, Bacterial; D006801:Humans; D010750:Phosphoproteins / Q000235:genetics / Q000378:metabolism; D039002:Prophages / Q000235:genetics* / Q000502:physiology; D012756:Sheep
chemical_list: D058947:Bacterial Secretion Systems; D029968:Escherichia coli Proteins; C457340:LEE protein, E coli; D010750:Phosphoproteins