title: IS900 targets translation initiation signals in Mycobacterium avium subsp. paratuberculosis to facilitate expression of its hed gene.
abstract: The Mycobacterium avium subsp. paratuberculosis (formerly Mycobacterium paratuberculosis) atypical insertion sequence, IS900, encodes a novel gene on the complementary strand to the putative transposase, p43. This gene requires a promoter, ribosome binding site (RBS) and termination codon to be acquired upon insertion into the M. avium subsp. paratuberculosis genome and hence is designated the hed (host expression-dependent) gene of IS900. Analysis of IS900 insertion sites suggests that this element targets translation initiation signals in M. avium subsp. paratuberculosis, specifically inserting between the RBS and start codon of a putative gene sequence. This aligns the hed initiation codon adjacent to a functional RBS and possibly downstream of an active promoter, driving expression of Hed protein. We have confirmed this unique targeting process by detecting expression of hed in M. avium subsp. paratuberculosis at the level of transcription by reverse transcription-PCR. Further, two Hed-specific antibodies detected Hed translation products in Western blots of protein extracts from M. avium subsp. paratuberculosis. A recombinant form of Hed expressed and purified from Escherichia coli will facilitate studies of IS900 transposition and will also be assessed as a diagnostic antigen for M. avium subsp. paratuberculosis disease. Implications of IS900 insertion in M. avium subsp. paratuberculosis pathogenicity are discussed.
authors.affiliation: Department of Surgery St Georges Hospital Medical School Cranmer Terrace London SW17 ORE UK.
authors.forename: Tim
authors.initials: T
authors.lastname: Doran
authors.affiliation: Department of Surgery St Georges Hospital Medical School Cranmer Terrace London SW17 ORE UK.
authors.forename: Mark
authors.initials: M
authors.lastname: Tizard
authors.affiliation: Department of Surgery St Georges Hospital Medical School Cranmer Terrace London SW17 ORE UK.
authors.forename: Douglas
authors.initials: D
authors.lastname: Millar
authors.affiliation: Department of Surgery St Georges Hospital Medical School Cranmer Terrace London SW17 ORE UK.
authors.forename: Jon
authors.initials: J
authors.lastname: Ford
authors.affiliation: Department of Surgery St Georges Hospital Medical School Cranmer Terrace London SW17 ORE UK.
authors.forename: Nazira
authors.initials: N
authors.lastname: Sumar
authors.affiliation: Department of Surgery St Georges Hospital Medical School Cranmer Terrace London SW17 ORE UK.
authors.forename: Mark
authors.initials: M
authors.lastname: Loughlin
authors.affiliation: Department of Surgery St Georges Hospital Medical School Cranmer Terrace London SW17 ORE UK.
authors.forename: John
authors.initials: J
authors.lastname: Hermon-Taylor
mesh_terms: D000907:Antibodies, Bacterial; D001426:Bacterial Proteins / Q000096:biosynthesis / Q000235:genetics* / Q000276:immunology; D004251:DNA Transposable Elements / Q000235:genetics*; D015964:Gene Expression Regulation, Bacterial; D005798:Genes, Bacterial; D005822:Genetic Vectors; D009162:Mycobacterium avium / Q000235:genetics*; D010442:Peptide Chain Initiation, Translational; D016133:Polymerase Chain Reaction; D014176:Protein Biosynthesis; D012329:RNA, Bacterial / Q000302:isolation & purification; D012333:RNA, Messenger / Q000302:isolation & purification; D014158:Transcription, Genetic
chemical_list: D000907:Antibodies, Bacterial; D001426:Bacterial Proteins; D004251:DNA Transposable Elements; C104797:Hed protein, Mycobacterium avium; D012329:RNA, Bacterial; D012333:RNA, Messenger