Abstract
A fluorescence-based approach was developed to analyze in vivo the function of Manduca sexta cadherin (Bt-R(1)) as a Cry1 toxin receptor. We cloned a Bt-R(1a) cDNA that differs from Bt-R(1) by 37 nucleotides and two amino acids and expressed it transiently in Drosophila melanogaster Schneider 2 (S2) cells. Cells expressing Bt-R(1a) bound Cry1Aa, Cry1Ab, and Cry1Ac toxins on ligand blots, and in saturation binding assays. More Cry1Ab was bound relative to Cry1Aa and Cry1Ac, though each Cry1A toxin bound with high-affinity (Kd values from 1.7 to 3.3 nM). Using fluorescent microscopy and flow cytometry assays, we show that Cry1Aa, Cry1Ab and Cry1Ac, but not Cry1Ba, killed S2 cells expressing Bt-R(1a) cadherin. These results demonstrate that M. sexta cadherin Bt-R(1a) functions as a receptor for the Cry1A toxins in vivo and validates our cytotoxicity assay for future receptor studies.
Publication types
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Research Support, Non-U.S. Gov't
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Research Support, U.S. Gov't, P.H.S.
MeSH terms
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Animals
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Bacillus thuringiensis / metabolism
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Bacillus thuringiensis Toxins
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Bacterial Proteins / metabolism*
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Bacterial Toxins / metabolism
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Base Sequence
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Cadherins / genetics
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Cadherins / metabolism*
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Cell Line
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DNA, Complementary / genetics
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Drosophila melanogaster
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Endotoxins / metabolism*
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Flow Cytometry
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Green Fluorescent Proteins
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Hemolysin Proteins
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Insect Proteins / genetics
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Insect Proteins / metabolism*
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Luminescent Proteins / genetics
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Luminescent Proteins / metabolism
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Manduca / genetics
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Manduca / metabolism*
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Microscopy, Fluorescence
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Receptors, Cell Surface / genetics
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Receptors, Cell Surface / metabolism*
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Recombinant Fusion Proteins / genetics
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Recombinant Fusion Proteins / metabolism
Substances
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Bacillus thuringiensis Toxins
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Bacterial Proteins
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Bacterial Toxins
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Cadherins
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Cry toxin receptors
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DNA, Complementary
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Endotoxins
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Hemolysin Proteins
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Insect Proteins
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Luminescent Proteins
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Receptors, Cell Surface
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Recombinant Fusion Proteins
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insecticidal crystal protein, Bacillus Thuringiensis
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Green Fluorescent Proteins