Cloning and Expression in Escherichia coli of an Insecticidal Crystal Protein Gene from Bacillus thuringiensis var. aizawai HD-133

SUMMARY: Using a gene probe derived from the cloned var. sotto insecticidal crystal protein (ICP) gene, we have cloned a Bacillus thuringiensis var. aizawai HD-133 ICP gene in Escherichia coli. The gene encodes a polypeptide that is toxic to Lepidoptera in vivo and in vitro. The protein is expressed at a level sufficient to produce phase-bright inclusions in recombinant E. coli strains, and these inclusions can be partially purified using discontinuous sucrose density gradients. Immunoblot- ting shows that the inclusions contain a 135 kDa polypeptide which reacts strongly with antiserum raised against the B. thuringiensis var. kurstaki HD-I P1 polypeptide.