An Arabidopsis thaliana cDNA complements the N-acetylglucosaminyltransferase I deficiency of CHO Lec1 cells

N-Acetylglucosaminyltransferase I(GlcNAcT-I, EC 2.4.1.101) is the enzyme wh ich initiates the formation of complex N-linked glycans in eukaryotes by tr ansforming GlcNAc to the oligo-mannosyl acceptor Man(5)GlcNAc(2)-Asn. The e nzymatic activity and the structure that is synthesised by this enzyme are found in animals and plants but not in yeast, cDNAs encoding the enzyme hav e already been cloned from several mammals and the nematode Caenorhabditis elegans. In this article the cloning of an Arabidopsis thaliana GlcNAcT-I c DNA with homology to animal cDNAs is described. By expression of the plant cDNA in CHO Led cells, a mammalian cell line deficient in GlcNAcT-I, it was shown that it encodes an active enzyme with the same enzymatic activity as the animal homologue, It has already been shown that a human GlcNAcT-I can complement an A thaliana mutant (cgl-1). Here it is shown that the reverse is also true, the plant glycosyltransferase is able to complement a mammal ian mutant (Lec1) deficient in GlcNAcT-I, (C) 1999 Academic Press.