Abstract: Four bacterial expression vectors were constructed, which carry the full-length, the N-end truncated, the C-end truncated soybean 24 kDa oleosin gene as well as the fused fragment with the genes encoding the heat-labile toxin B subunit and CS6 B subunit from E.coli. The growth of host cells was depressed when the full-length 24 kDa oleosin gene was expressed in E. coli either as the native fragment or as a tandem unit fused with bacterial genes, with a reduction to about one-third of the growth rate of control culture. Deletion of the DNA sequence encoding 152 amino acids near the C terminus of the 24 kDa oleosin could not overcome this toxicity. However, the toxicity can be overcomed by deletion of the sequence encoding the 74 amino acids of the N terminal region of the protein. When products induced by IPTG were detected by SDS-PAGE and Western blotting, only the 24 kDa oleosin gene fragment truncated 222 oligonucleotides at N terminus could express and accumulate the target protein in E.coli host BL21(DE3) or Rosseta(DE3).

Key words: Soybean, Oleosin, Expression, Escherichia coli