Two frameshift products involved in the transposition of bacterial insertion sequence IS629.
IS629 is 1,310 bp in length with a pair of 25-bp imperfect inverted repeats at its termini. Two partially overlapping open reading frames, orfA and orfB, are present in IS629, and two putative translational frameshift signals, TTTTG (T4G) and AAAAT (A4T), are located near the 3'-end of orfA. With the lacZ gene as the reporter, both T4G and A4T motifs are determined to be a -1 frameshift signal. Two peptides representing the two transframe products designated OrfAB' and OrfAB, are identified by a liquid chromatography-tandem mass spectrometric approach. Results of transposition assays show that OrfAB' is the transposase and that OrfAB aids in the transposition of IS629. Pulse-chase experiments and Escherichia coli two-hybrid assays demonstrate that OrfAB binds to and stabilizes OrfAB', thus increasing the transposition activity of IS629. This is the first transposable element in the IS3 family shown to have two functional frameshifted products involved in transposition and to use a transframe product to regulate transposition.
Chen
Chang-Chieh
CC
Institute of Microbiology and Immunology, School of Life Sciences, National Yang-Ming University, No. 155, Li-Nong St., Sec. 2, Shih-Pai, Taipei 112, Taiwan.
Hu
Shiau-Ting
ST
Institute of Microbiology and Immunology, School of Life Sciences, National Yang-Ming University, No. 155, Li-Nong St., Sec. 2, Shih-Pai, Taipei 112, Taiwan; Department of Microbiology, School of Medicine, National Yang-Ming University, No. 155, Li-Nong St., Sec. 2, Shih-Pai, Taipei 112, Taiwan. Electronic address: tingnahu@ym.edu.tw.
D020816:Amino Acid Motifs; D004251:DNA Transposable Elements / Q000235:genetics*; D004926:Escherichia coli; D016368:Frameshift Mutation / Q000235:genetics*; D005798:Genes, Bacterial / Q000235:genetics*; D016366:Open Reading Frames; D012091:Repetitive Sequences, Nucleic Acid; D012764:Shigella sonnei / Q000235:genetics; D019895:Transposases; D020798:Two-Hybrid System Techniques
D004251:DNA Transposable Elements; D019895:Transposases