A 250 kDa glycoprotein isolated from the apical brush border membrane of Asiatic corn borer Ostrinia furnacalis is the binding receptor of Cry 1AB protein from Bacillus thuringiensis
2003
Alcantara, E.P. (Philippines Univ. Los Banos, College, Laguna (Philippines). National Inst. of Molecular Biology and Biotechnology)
Brush border membrane vesicles (BBMVs) were prepared from isolated larval midguts of Asiatic corn borer Ostrinia furnacalis. SDS-PAGE [sodium dodecyl sulfate-polyacrylamide gel electrophoresis] analysis of detergent-solubilized BBMVs revealed four major protein bands with molecular sizes ranging from 80 kDa to greater than 250 kDa. Ligand blot analysis of the PVDF membrane-immobilized BBMV proteins revealed that the 250 kDa protein is the receptor for Bacillus thuringiensis Cry1AB protein binding. The other BBMV proteins detected by SDS-PAGE might represent apical midgut membrane integral proteins such as ion channels and symporters. These proteins are essential for normal function of the midgut and thus could also serve as targets of novel inhibitors. Immunoblot analysis also showed that the 250 kDa receptor cross-reacted with gypsy moth Lymantria dispar anti-aminopeptidase N. Binding to aminopeptidase N (APN) determines insect specificity and insecticidal activity. In the majority of cases, modification of APN is the basis of insect resistance to Cry proteins. Glycosylation of the 250 kDa receptor protein was detected and might be a post-translational factor for Cry1AB
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