Genetic model organisms in the study of N-glycans

Recently the genomic sequences of three multicellular eukaryotes, Caenorhab ditis elegans, Drosophila Melanogaster and Arabidopsis thaliana, have been elucidated. A number of cDNAs encoding glycosyltransferases demonstrated to have a role in N-linked glycosylation have already been cloned from these organisms, e.g., GlcNAc transferases and alphal,3-fucosyltransferases. Howe ver, many more homologues of glycosyltransferases and other glycan modifyin g enzymes have been predicted by analysis of the genome sequences, but the predictions of full length open reading frames appear to be particularly po or in Caenorhabditis. The use of these organisms as models in glycobiology may be hampered since they all have N-linked glycosylation repertoires unli ke those of mammals. Arabidopsis and Drosophila have glycosylation similar to that of other plants or insects, while our new data from MALDI-TOF analy sis of PNGase A-released neutral N-glycans of Caenorhabditis indicate that there exists a range of pauci- and oligomannosidic structures, with up to f our fucose residues and up to two O-methyl groups. With all these three 'ge netic model organisms', however, much more work is required for a full unde rstanding of their glycobiology. (C) 2001 Societe francaise de biochimie et biologie moleculaire/Editions scientifiques et medicales Elsevier SAS. All rights reserved.