title: A novel strong promoter of the groEx operon of symbiotic bacteria in Amoeba proteus.
abstract: Gram- symbiotic bacteria (called X-bacteria), present in the xD strain of Amoeba proteus as required cell components, contain a large amount of a 67-kDa protein, a GroEL analog. The complete nucleotide (nt) sequence of the groEx operon of X-bacteria has been determined and it has a high degree of nt identity with those of other bacterial groE operons. The groELx gene is expressed in transformed Escherichia coli and has a novel and potent promoter (P2) in addition to the heat-shock consensus promoter (P1). This is shown by the production of GroELx in Escherichia coli transformed with modified DNA clones lacking P1 and by an enhanced production of a GroELx::beta-galactosidase fusion protein when a portion of groEx containing P2 is linked to the lacZ gene. Primer-extension analyses revealed the presence of possible P2 sequences within the open reading frame of the groESx gene. It is suggested that the presence of a potent P2 in the X-bacterial gene is an adaptation for the endosymbiotic bacteria to survive within a potentially hostile intracellular environment.
authors.affiliation: Department of Zoology, University of Tennessee, Knoxville 37996.
authors.forename: T I
authors.initials: TI
authors.lastname: Ahn
authors.forename: S T
authors.initials: ST
authors.lastname: Lim
authors.forename: H K
authors.initials: HK
authors.lastname: Leeu
authors.forename: J E
authors.initials: JE
authors.lastname: Lee
authors.forename: K W
authors.initials: KW
authors.lastname: Jeon
mesh_terms: D000595:Amino Acid Sequence; D000656:Amoeba / Q000382:microbiology*; D000818:Animals; D001426:Bacterial Proteins / Q000096:biosynthesis / Q000235:genetics*; D001483:Base Sequence; D018833:Chaperonins; D003001:Cloning, Molecular; D004926:Escherichia coli / Q000235:genetics; D029968:Escherichia coli Proteins; D015964:Gene Expression Regulation, Bacterial / Q000235:genetics; D006090:Gram-Negative Bacteria / Q000235:genetics*; D006360:Heat-Shock Proteins / Q000096:biosynthesis / Q000235:genetics*; D008969:Molecular Sequence Data; D009876:Operon / Q000235:genetics*; D011401:Promoter Regions, Genetic / Q000235:genetics*; D011993:Recombinant Fusion Proteins / Q000096:biosynthesis; D017422:Sequence Analysis, DNA; D012689:Sequence Homology, Nucleic Acid; D013559:Symbiosis
chemical_list: D001426:Bacterial Proteins; D029968:Escherichia coli Proteins; C028715:GroE protein, E coli; D006360:Heat-Shock Proteins; D011993:Recombinant Fusion Proteins; D018833:Chaperonins