Arabidopsis glucosidase I mutants reveal a critical role of N-glycan trimming in seed development

EMBO J. 2001 Mar 1;20(5):1010-9. doi: 10.1093/emboj/20.5.1010.


Glycoproteins with asparagine-linked (N-linked) glycans occur in all eukaryotic cells. The function of their glycan moieties is one of the central problems in contemporary cell biology. N-glycosylation may modify physicochemical and biological protein properties such as conformation, degradation, intracellular sorting or secretion. We have isolated and characterized two allelic Arabidopsis mutants, gcs1-1 and gcs1-2, which produce abnormal shrunken seeds, blocked at the heart stage of development. The mutant seeds accumulate a low level of storage proteins, have no typical protein bodies, display abnormal cell enlargement and show occasional cell wall disruptions. The mutated gene has been cloned by T-DNA tagging. It codes for a protein homologous to animal and yeast alpha-glucosidase I, an enzyme that controls the first committed step for N-glycan trimming. Biochemical analyses have confirmed that trimming of the alpha1,2- linked glucosyl residue constitutive of the N-glycan precursor is blocked in this mutant. These results demonstrate the importance of N-glycan trimming for the accumulation of seed storage proteins, the formation of protein bodies, cell differentiation and embryo development.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Alleles
  • Amino Acid Sequence
  • Arabidopsis / embryology
  • Arabidopsis / enzymology*
  • Arabidopsis / genetics
  • Arabidopsis / ultrastructure
  • Cell Differentiation
  • Cloning, Molecular
  • DNA, Bacterial / genetics
  • Gene Expression Profiling
  • Gene Expression Regulation, Plant
  • Genes, Essential / genetics
  • Genetic Complementation Test
  • Glycosylation
  • Histocytochemistry
  • Immunoblotting
  • Microscopy, Electron
  • Molecular Sequence Data
  • Mutation / genetics*
  • Phenotype
  • Polysaccharides / chemistry
  • Polysaccharides / metabolism*
  • RNA, Messenger / analysis
  • RNA, Messenger / genetics
  • Seeds / embryology
  • Seeds / enzymology*
  • Seeds / genetics
  • Seeds / ultrastructure
  • Sequence Homology, Amino Acid
  • Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
  • alpha-Glucosidases / chemistry
  • alpha-Glucosidases / genetics*
  • alpha-Glucosidases / metabolism*


  • DNA, Bacterial
  • Polysaccharides
  • RNA, Messenger
  • T-DNA
  • glucosidase I
  • alpha-Glucosidases