[Comparative study of 3 heterologous expression systems for obtaining recombinant Bacillus thuringiensis delta-endotoxins].

cryIA(b) and cryIA(c) genes encoding active fragments of Bacillus thuringiensis delta-endotoxins were cloned downstream of the pR and pT7 promoters from the lambda and T7 bacteriophages, respectively. cryIA(b) gene was also fused with the gene encoding protein A from Staphylococcus aureus cloned under the control of the pR promoter. There were no remarkable differences in the expression levels of the cloned genes in E. coli, but the Western blot analysis allowed distinct protein quality for the three expression systems. We conclude that the best expression model for the production of delta-endotoxins toxic fragments in E. coli is the one based on lambda pR promoter.