A leader open reading frame is essential for the expression in Escherichia coli of GC-rich leuB gene of an extreme thermophile, Thermus thermophilus

Authors

  • Masami Ishida,

    Corresponding author
    1. Laboratory of Biochemistry of Marine Resources, Tokyo University of Fisheries, Konan 4, Minato-ku, Tokyo 108, Japan
      *Corresponding author. Tel: +81 (3) 5463 0586; Fax: +81 (3) 5463 0589.
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  • Tairo Oshima

    1. Department of Molecular Biology, Tokyo University of Pharmacy and Life Science, Hachioji, Tokyo 192-03, Japan
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*Corresponding author. Tel: +81 (3) 5463 0586; Fax: +81 (3) 5463 0589.

Abstract

Abstract To improve expression efficiency of the leuB gene of an extreme thermophile, Thermus thermophilus, in Escherichia coli, the gene was placed under a potent promoter, tac. However, the expression was hardly improved, despite increased transcription. The expression under tac promoter was significantly improved by introducing a leader open reading frame in front of the gene. Similar improvement under a weak promoter, tet, with a leader open reading frame had been described previously. The present results provide evidence that the major limiting step in the expression of a GC-rich thermophile gene in E. coli is translation, and that the addition of a leader open reading frame is more crucial for high level expression of the gene than the use of a potent promoter.

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