IS900 targets translation initiation signals in Mycobacterium avium subsp. paratuberculosis to facilitate expression of its hed gene.
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.
Doran
Tim
T
Department of Surgery St Georges Hospital Medical School Cranmer Terrace London SW17 ORE UK.
Tizard
Mark
M
Department of Surgery St Georges Hospital Medical School Cranmer Terrace London SW17 ORE UK.
Millar
Douglas
D
Department of Surgery St Georges Hospital Medical School Cranmer Terrace London SW17 ORE UK.
Ford
Jon
J
Department of Surgery St Georges Hospital Medical School Cranmer Terrace London SW17 ORE UK.
Sumar
Nazira
N
Department of Surgery St Georges Hospital Medical School Cranmer Terrace London SW17 ORE UK.
Loughlin
Mark
M
Department of Surgery St Georges Hospital Medical School Cranmer Terrace London SW17 ORE UK.
Hermon-Taylor
John
J
Department of Surgery St Georges Hospital Medical School Cranmer Terrace London SW17 ORE UK.
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
D000907:Antibodies, Bacterial; D001426:Bacterial Proteins; D004251:DNA Transposable Elements; C104797:Hed protein, Mycobacterium avium; D012329:RNA, Bacterial; D012333:RNA, Messenger