Expression of the Full-Length and 3′-Spliced cry 1Ab Gene in the 135-kDa Crystal Protein Minus Derivative of Bacillus thuringiensis subsp. kyushuensis

Bacillus thuringiensis produces a 130 –135-kDa insecticidal protein in the form of bipyramidal crystal which is toxic to lepidopteran larvae. Part of the C-terminal region of the native Cry1Ab was replaced by a heterologous sequence of Cry11Aa C-terminus to get a 3 -spliced cry 1Ab gene. The full-length cry 1Ab and 3 -spliced cry 1Ab, which were both cloned into the E. coli–B. thuringiensis shuttle expression vector pHZB1, were expressed in a 135-kDa crystal protein minus derivative of B. thuringiensis subsp. kyushuensis (4U1-Cry 135 ). The crystal shape of Cry1Ab proteins from both recombinants was regularly bipyramidal, while the crystal size of the intact Cry1Ab was approximately fivefold larger than the 3 -spliced Cry1Ab. In addition, these two kinds of Cry1Ab proteins had similar toxicity against Argyrogramma agnata larvae