title: The excision proteins of CTnDOT positively regulate the transfer operon.
abstract: The Bacteroides conjugative transposon, CTnDOT, is an integrated conjugative element (ICE), found in many human colonic Bacteroides spp. strains. It has a complex regulatory system for both excision from the chromosome and transfer and mobilization into a new host. It was previously shown that a cloned DNA segment encoding the xis2c, xis2d, orf3, and exc genes was required for tetracycline dependent activation of the P(tra) promoter. The Xis2c and Xis2d proteins are required for excision while the Exc protein stimulates excision. We report here that neither the Orf3 nor the Exc proteins are involved in activation of the P(tra) promoter. Deletion analysis and electromobility shift assays showed that the Xis2c and Xis2d proteins bind to the P(tra) promoter to activate the tra operon. Thus, the recombination directionality factors of CTnDOT excision also function as activator proteins of the P(tra) promoter.
authors.affiliation: Department of Microbiology, University of Illinois at Urbana-Champaign, 601 S. Goodwin Avenue, Urbana, IL 61801, USA. ckeeton2@illinois.edu
authors.forename: Carolyn M
authors.initials: CM
authors.lastname: Keeton
authors.forename: Jiyeon
authors.initials: J
authors.lastname: Park
authors.forename: Gui-Rong
authors.initials: GR
authors.lastname: Wang
authors.forename: Crystal M
authors.initials: CM
authors.lastname: Hopp
authors.forename: Nadja B
authors.initials: NB
authors.lastname: Shoemaker
authors.forename: Jeffrey F
authors.initials: JF
authors.lastname: Gardner
authors.forename: Abigail A
authors.initials: AA
authors.lastname: Salyers
mesh_terms: D001426:Bacterial Proteins / Q000378:metabolism*; D001439:Bacteroides / Q000187:drug effects / Q000235:genetics*; D001483:Base Sequence; D003227:Conjugation, Genetic / Q000187:drug effects; D004251:DNA Transposable Elements / Q000235:genetics*; D024202:Electrophoretic Mobility Shift Assay; D017353:Gene Deletion; D005966:Glucuronidase / Q000378:metabolism; D006801:Humans; D008969:Molecular Sequence Data; D009876:Operon / Q000235:genetics*; D011401:Promoter Regions, Genetic / Q000235:genetics; D013752:Tetracycline / Q000494:pharmacology
chemical_list: D001426:Bacterial Proteins; D004251:DNA Transposable Elements; D005966:Glucuronidase; D013752:Tetracycline