Cadherin-like receptor from the European corn borer (Ostrinia nubilalis) for Bacillus thuringiensis cry1A toxins [electronic resource].

Includes references.

Bacillus thuringiensis Cry1A toxins are lethal to the corn pest European corn borer (Ostrinia nubilalis) larvae. Cry1Aa, Cry1Ab and Cry1Ac bind to a protein of -205-kDa in the brush porder membrane vesicles. In addition, Cry1Ab binds to proteins of - 150 and 170-kDa and Cry1Ac binds to proteins of -120 kDa. A competition ligand blot using unlabeled Cry1Ab to compete with ¹²⁵I.CryiAb shows that binding to the 150, 170 and 205-kDa proteins is compateted away by CryiAb. Furthermore, toxin-receptor dissociation constant Kd shows that the binding occurs with high affinity (Kd - 1.2 nM). These results suggest that Cry1Aa, CryiAb and Crv1Ac share a 205-kDa common membrane biading protein and they bind specifically with high affinity. The Southern blot and polymerase chain reaction analysis show that O. nubilalis contains a homologue to the 210-kDa Manduca Sexta BT-R₁ cadherin-like receptor which mediates toxicity for Cry1A toxins. Consequently, these results suggest that the 205-kDa protein band is a cadherin-like receptor homologous to the 210-kDa tobacco horn worm receptor. Therefore, it is more likely that the 205-kDa receptor is mediating toxicity to O. nubilalis but not the 120,150 or 170-kDa proteins.

Summary in Arabic.

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