Complete nucleotide sequence of Tn1721: gene organization and a novel gene product with features of a chemotaxis protein.
The complete 11,139-nucleotide sequence of transposon Tn1721 has been determined. It contains three 38-bp inverted repeats, and (in this order) a new orfI, a resolution site (res), genes encoding resolvase (tnpR), transposase (tnpA), tetracycline-resistance (TcR) repressor (tetR), TcR (tetA) and a truncated transposase gene (tnpA'). The modulator origin of Tn1721 from at least three separate sources is supported by the distinctive codon usages of orfI, tnpR/tnpA and tetR/tetA, and by sequence similarities with Tn501 (tnpR/tnpA) and RP1 (tetR/tetA). The ORFI-encoded 56-kDa polypeptide exhibits features of a methyl-accepting chemotaxis protein (MCP) with a conserved signal domain and a potential transmembrane domain; this polypeptide cross-reacts with anti-MCP antiserum. Like chemotaxis genes, orfI is transcribed from a sigma 28-like promoter. The overexpressed orfI gene product interferes with MCP-dependent chemotaxis suggesting that it completes for soluble transducer protein(s) in the cell. The potential selective advantage of this novel transposon-borne gene is discussed.
Allmeier
H
H
Lehrstuhl für Genetik, Universität Regensburg, F.R.G.
Cresnar
B
B
Greck
M
M
Schmitt
R
R
D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000235:genetics*; D001483:Base Sequence; D005075:Biological Evolution; D015153:Blotting, Western; D002630:Chemotactic Factors / Q000235:genetics*; D004247:DNA; D004251:DNA Transposable Elements; D029968:Escherichia coli Proteins; D008565:Membrane Proteins / Q000235:genetics*; D000072236:Methyl-Accepting Chemotaxis Proteins; D008969:Molecular Sequence Data; D016366:Open Reading Frames; D011401:Promoter Regions, Genetic; D015183:Restriction Mapping; D016415:Sequence Alignment; D015398:Signal Transduction / Q000235:genetics; D014158:Transcription, Genetic
D001426:Bacterial Proteins; D002630:Chemotactic Factors; D004251:DNA Transposable Elements; D029968:Escherichia coli Proteins; D008565:Membrane Proteins; D000072236:Methyl-Accepting Chemotaxis Proteins; D004247:DNA