CLONING OF AN INSECTICIDAL CHOLESTEROL OXIDASE GENE AND ITS EXPRESSION IN BACTERIA AND IN PLANT-PROTOPLASTS

We cloned and sequenced structural gene choM, which encodes an insecti cidally active cholesterol oxidase in Streptomyces sp. strain A19249. The primary translation product was predicted to be a 547-amino-acid p rotein whose first 43 amino acids constitute a secretory signal peptid e. Expression of the gene with the signal sequence in Escherichia. coi l resulted in production of a protein that had enzymatic and insectici dal properties which were indistinguishable from those of the choleste rol oxidase secreted by Streptomyces sp. strain A19249. Expression of the gene with or without the signal sequence in tobacco protoplasts re sulted in production of an enzymatically active cholesterol oxidase.