The Drosophila melanogaster homologue of the human histo-blood group Pk gene encodes a glycolipid-modifying alpha1,4-N-acetylgalactosaminyltransferase.
Insects express arthro-series glycosphingolipids, which contain an alpha1,4-linked GalNAc residue. To determine the genetic basis for this linkage, we cloned a cDNA (CG17223) from Drosophila melanogaster encoding a protein with homology to mammalian alpha1,4-glycosyltransferases and expressed it in the yeast Pichia pastoris. Culture supernatants from the transformed yeast were found to display a novel UDP-GalNAc:GalNAcbeta1,4GlcNAcbeta1-R alpha-N-acetylgalactosaminyltransferase activity when using either a glycolipid, p-nitrophenylglycoside or an N-glycan carrying one or two terminal beta-N-acetylgalactosamine residues. NMR and MS in combination with glycosidase digestion and methylation analysis indicate that the cloned cDNA encodes an alpha1,4-N-acetylgalactosaminyltransferase. We hypothesize that this enzyme and its orthologues in other insects are required for the biosynthesis of the N5a and subsequent members of the arthro-series of glycolipids as well as of N-glycan receptors for Bacillus thuringiensis crystal toxin Cry1Ac.
Mucha
Ján
J
Chemický ústav, Slovenská akadémia vied, Dúbravská cesta 9, 845 38 Bratislava, Slovakia.
Domlatil
Jirí
J
Lochnit
Günter
G
Rendić
Dubravko
D
Paschinger
Katharina
K
Hinterkörner
Georg
G
Hofinger
Andreas
A
Kosma
Paul
P
Wilson
Iain B H
IB
D000595:Amino Acid Sequence / Q000235:genetics; D000818:Animals; D002240:Carbohydrate Sequence / Q000235:genetics; D003001:Cloning, Molecular / Q000379:methods; D029721:Drosophila Proteins / Q000737:chemistry / Q000235:genetics; D004331:Drosophila melanogaster / Q000201:enzymology / Q000235:genetics*; D015971:Gene Expression Regulation, Enzymologic / Q000235:genetics; D006017:Glycolipids / Q000378:metabolism*; D006801:Humans; D008018:Life Cycle Stages / Q000235:genetics; D008969:Molecular Sequence Data; D017350:N-Acetylgalactosaminyltransferases / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D009596:Nitrophenols / Q000378:metabolism; D010127:P Blood-Group System / Q000235:genetics*; D017386:Sequence Homology, Amino Acid; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization / Q000379:methods; D013379:Substrate Specificity
D029721:Drosophila Proteins; D006017:Glycolipids; D009596:Nitrophenols; D010127:P Blood-Group System; D017350:N-Acetylgalactosaminyltransferases; C024836:4-nitrophenol