Resistance to Bacillus thuringiensis toxin in Caenorhabditis elegans from loss of fucose.
A mutation in the Caenorhabditis elegans bre-1 gene was isolated in a screen for Bacillus thuringiensis toxin-resistant (bre) mutants to the Cry5B crystal toxin made by B. thuringiensis. bre-1 mutant animals are different from the four other cloned bre mutants in that their level of resistance is noticeably lower. bre-1 animals also display a significantly reduced brood size at 25 degrees C. Here we cloned the bre-1 gene and characterized the bre-1 mutant phenotype. bre-1 encodes a protein with significant homology to a GDP-mannose 4,6-dehydratase, which catalyzes the first step in the biosynthesis of GDP-fucose from GDP-mannose. Injection of GDP-fucose but not fucose into C. elegans intestinal cells rescues bre-1 mutant phenotypes. Thus, C. elegans lacks a functional fucose salvage pathway. Furthermore, we demonstrate that bre-1 mutant animals are defective in production of fucosylated glycolipids and that bre-1 mutant animals make quantitatively reduced levels of glycolipid receptors for Cry5B. We finally show that bre-1 mutant animals, although viable, show a lack of fucosylated N- and O-glycans, based on mass spectrometric evidence. Thus, C. elegans can survive with little fucose and can develop resistance to crystal toxin by loss of a monosaccharide biosynthetic pathway.
Barrows
Brad D
BD
Section of Cell and Developmental Biology, University of California, San Diego, La Jolla, California 92093-0349, USA.
Haslam
Stuart M
SM
Bischof
Larry J
LJ
Morris
Howard R
HR
Dell
Anne
A
Aroian
Raffi V
RV
D000818:Animals; D001427:Bacterial Toxins / Q000633:toxicity*; D017173:Caenorhabditis elegans / Q000187:drug effects / Q000235:genetics / Q000502:physiology*; D029742:Caenorhabditis elegans Proteins / Q000235:genetics; D003001:Cloning, Molecular; D017931:DNA Primers; D004351:Drug Resistance; D005643:Fucose / Q000172:deficiency*; D005700:Galactosyltransferases / Q000235:genetics; D008297:Male; D016133:Polymerase Chain Reaction; D020641:Polymorphism, Single Nucleotide; D012098:Reproduction
C049673:Bacillus thuringiensis ovicidal toxin; D001427:Bacterial Toxins; D029742:Caenorhabditis elegans Proteins; D017931:DNA Primers; D005643:Fucose; C433229:BRE-5 protein, C elegans; D005700:Galactosyltransferases