COBRA encodes a putative GPI-anchored protein, which is polarly localized and necessary for oriented cell expansion in Arabidopsis

Genes Dev. 2001 May 1;15(9):1115-27. doi: 10.1101/gad.879101.

Abstract

To control organ shape, plant cells expand differentially. The organization of the cellulose microfibrils in the cell wall is a key determinant of differential expansion. Mutations in the COBRA (COB) gene of Arabidopsis, known to affect the orientation of cell expansion in the root, are reported here to reduce the amount of crystalline cellulose in cell walls in the root growth zone. The COB gene, identified by map-based cloning, contains a sequence motif found in proteins that are anchored to the extracellular surface of the plasma membrane through a glycosylphosphatidylinositol (GPI) linkage. In animal cells, this lipid linkage is known to confer polar localization to proteins. The COB protein was detected predominately on the longitudinal sides of root cells in the zone of rapid elongation. Moreover, COB RNA levels are dramatically upregulated in cells entering the zone of rapid elongation. Based on these results, models are proposed for the role of COB as a regulator of oriented cell expansion.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Amino Acid Sequence
  • Apoproteins
  • Arabidopsis / cytology*
  • Arabidopsis / genetics*
  • Arabidopsis / metabolism
  • Arabidopsis Proteins*
  • Base Sequence
  • Cell Membrane / metabolism
  • Cell Polarity / physiology*
  • Cellulose / metabolism
  • Chromosome Mapping
  • Cloning, Molecular
  • Cytochrome b Group
  • Cytochromes b
  • Gene Expression Regulation, Plant
  • Glycosylphosphatidylinositols / metabolism
  • Membrane Glycoproteins / genetics*
  • Membrane Glycoproteins / metabolism*
  • Molecular Sequence Data
  • Mutation
  • Plant Roots / cytology
  • RNA, Plant / metabolism

Substances

  • Apoproteins
  • Arabidopsis Proteins
  • COB protein, Arabidopsis
  • Cytochrome b Group
  • Glycosylphosphatidylinositols
  • Membrane Glycoproteins
  • RNA, Plant
  • Cellulose
  • Cytochromes b

Associated data

  • GENBANK/AA556615
  • GENBANK/AF319663
  • GENBANK/AI166150
  • GENBANK/AI416924
  • GENBANK/AI730765
  • GENBANK/AI773156
  • GENBANK/AI861761
  • GENBANK/AJ006787
  • GENBANK/AW559872
  • GENBANK/AW720520
  • GENBANK/BE130595
  • GENBANK/H74542