Identification, cloning and expression of a Cry1Ab cadherin receptor from European corn borer, Ostrinia nubilalis (Hübner) (Lepidoptera: Crambidae)
Document Type Article
Published in Insect Biochemistry and Molecular Biology 35:1 (January 2005), pp. 33-40. doi:10.1016/j.ibmb.2004.10.001 http://www.sciencedirect.com/science/journal/09651748 Copyright © 2004 Elsevier Ltd. Used by permission.
Transgenic corn expressing the Cry1Ab toxin from Bacillus thuringiensis is highly toxic to European corn borer, Ostrinia nubilalis, larvae. A putative Cry1Ab receptor (OnBt-R1) molecule was cloned and sequenced from a cDNA library prepared from midgut tissue of O. nubilalis larvae. The 5.6 Kb gene is homologous with a number of cadherin genes identified as Cry1 binding proteins in other lepidopterans. Brush border membrane vesicles were prepared using dissected midguts from late instars. A 220-kDa protein was identified as a cadherin-like molecule, which bound to Cry1Ab toxin and cross-reacted with an anti-cadherin serum developed from recombinant expression of a partial O. nubilalis cadherin peptide. Two additional proteins of smaller size cross-reacted with the anti-cadherin serum indicating that Cry1Ab binds to multiple receptors or to different forms of the same protein. Spodoptera frugiperda (SF9) cells transfected with the OnBt- R1 gene were shown to express the receptor molecule which caused functional susceptibility to Cry1Ab at concentrations as low as 0.1 μg/ml. These results in combination suggest strongly that a cadherin-like protein acts as receptor and is involved with Cry1Ab toxicity in O. nubilalis.