title: Mutants in DEFECTIVE GLYCOSYLATION, an Arabidopsis homolog of an oligosaccharyltransferase complex subunit, show protein underglycosylation and defects in cell differentiation and growth.
abstract: A mutant called defective glycosylation1-1 (dgl1-1) was identified in Arabidopsis based on a growth defect of the dark-grown hypocotyl and an abnormal composition of the non-cellulosic cell wall polysaccharides. dgl1-1 is altered in a protein ortholog of human OST48 or yeast WBP1, an essential protein subunit of the oligosaccharyltransferase (OST) complex, which is responsible for the transfer in the ER of the N-linked glycan precursor onto Asn residues of candidate proteins. Consistent with the known function of the OST complex in eukaryotes, the dgl1-1 mutation led to a reduced N-linked glycosylation of the ER-resident protein disulfide isomerase. A second more severe mutant (dgl1-2) was embryo-lethal. Microscopic analysis of dgl1-1 revealed developmental defects including reduced cell elongation and the collapse and differentiation defects of cells in the central cylinder. These defects were accompanied by changes in the non-cellulosic polysaccharide composition, including the accumulation of ectopic callose. Interestingly, in contrast to other dwarf mutants that are altered in early steps of the N-glycan processing, dgl1-1 did not exhibit a cellulose deficiency. Together, these results confirm the role of DGL1 in N-linked glycosylation, cell growth and differentiation in plants.
authors.affiliation: Unité Mixte de Recherche 6037 Centre National de la Recherche Scientifique, IFRMP 23, Faculté des Sciences, Université de Rouen, 76821 Mont Saint Aignan Cedex, France.
authors.forename: Olivier
authors.initials: O
authors.lastname: Lerouxel
authors.forename: Grégory
authors.initials: G
authors.lastname: Mouille
authors.forename: Christine
authors.initials: C
authors.lastname: Andème-Onzighi
authors.forename: Marie-Pierre
authors.initials: MP
authors.lastname: Bruyant
authors.forename: Martial
authors.initials: M
authors.lastname: Séveno
authors.forename: Corinne
authors.initials: C
authors.lastname: Loutelier-Bourhis
authors.forename: Azeddine
authors.initials: A
authors.lastname: Driouich
authors.forename: Herman
authors.initials: H
authors.lastname: Höfte
authors.forename: Patrice
authors.initials: P
authors.lastname: Lerouge
mesh_terms: D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000166:cytology / Q000235:genetics / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D002454:Cell Differentiation / Q000235:genetics / Q000502:physiology*; D002473:Cell Wall; D015870:Gene Expression; D006031:Glycosylation; D006602:Hexosyltransferases / Q000235:genetics / Q000378:metabolism*; D018546:Hypocotyl / Q000648:ultrastructure; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism*; D008969:Molecular Sequence Data; D009154:Mutation; D010641:Phenotype; D018517:Plant Roots / Q000648:ultrastructure; D030821:Plants, Genetically Modified; D017386:Sequence Homology, Amino Acid
chemical_list: D029681:Arabidopsis Proteins; C502738:DGL1 protein, Arabidopsis; D008565:Membrane Proteins; D006602:Hexosyltransferases; C025620:dolichyl-diphosphooligosaccharide - protein glycotransferase