USE OF AN OPERON FUSION TO INDUCE EXPRESSION AND CRYSTALLIZATION OF ABACILLUS-THURINGIENSIS DELTA-ENDOTOXIN ENCODED BY A CRYPTIC GENE

A delta-endotoxin gene previously cloned from Bacillus thuringiensis s ubsp. galleriae has been shown by a combination of restriction mapping and DNA sequence analysis to be a cryIIB clone; in common with other cyIIB genes it was found to lack a functional promoter. Addition of a promoter resulted in expression of the gene in Bacillus thuringiensis but did not result in the formation of the crystalline inclusions norm ally associated with such toxins. Inclusion formation was only observe d when the gene was incorporated into an operon containing a gene know n to be involved in the crystallisation of another delta-endotoxin.