CLONING AND EXPRESSION OF A RECEPTOR FOR AN INSECTICIDAL TOXIN OF BACILLUS-THURINGIENSIS

Environmentally friendly toxins of Bacillus thuringiensis are effectiv e in controlling agriculturally and biomedically harmful insects. Howe ver, little is known about the insect receptor molecules that bind the se toxins and the mechanism of insecticidal activity. We report here f or the first time the cloning and expression of a cDNA that encodes a receptor (BT-R(1)) of the tobacco hornworm Manduca sexta for an insect icidal toxin of B. thuringiensis. The receptor is a 210-kDa membrane g lycoprotein that specifically binds the cryIA(b) toxin of B, thuringie nsis subsp. berliner and leads to death of the hornworm. BT-R(1) share s sequence similarity with the cadherin superfamily of proteins.