Isolation, characterization and immunolocalization of a novel, modular tomato arabinogalactan-protein corresponding to the LeAGP-1 gene

Plant J. 1999 Apr;18(1):43-55. doi: 10.1046/j.1365-313x.1999.00428.x.


Arabinogalactan-proteins (AGPs) are a family of hydroxy-proline-rich glycoproteins implicated to function in plant growth and development. This report focuses on a novel, modular AGP found in tomato, LeAGP-1, which was predicted by DNA cloning and herein verified at the protein level as a major AGP component. LeAGP-1 was isolated from tomato suspension-cultured cells and verified to be an AGP by precipitation with (beta-D-galactosyl)3 Yariv phenylglycoside and by amino acid composition analysis. Furthermore, LeAGP-1 was determined to correspond to LeAGP-1 clones based on three criteria: (1) amino acid composition identity, (2) amino acid sequence identity, and (3) specific immunoreactivity of glycosylated and deglycosylated LeAGP-1 with an antibody developed against the highly basic subdomain predicted from LeAGP-1 clones. The antibody was also used to immunolocalize LeAGP-1 in tomato to the cell surface of suspension-cultured cells, maturing metaxylem elements in young internodes and petioles, and stylar transmitting tissue cells. At the subcellular level, LeAGP-1 immunolocalized to the cell walls of these particular cells as well as to intercellular spaces between stylar transmitting tissue cells. LeAGP-1 now emerges as one of the most comprehensively studied AGPs in terms of (1) characterization at the genomic DNA, cDNA and protein levels, (2) known organ-specific and developmentally regulated mRNA expression patterns, (3) development of an antibody against a unique, peptide subdomain which specifically recognizes LeAGP-1 in its glycosylated and deglycosylated states, and (4) immunolocalization of a single, well-defined AGP molecule at the tissue and subcellular levels.

Publication types

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

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Antibody Specificity
  • Cell Wall / metabolism
  • Cloning, Molecular
  • DNA, Complementary / genetics
  • DNA, Plant / genetics
  • Genes, Plant*
  • Immunohistochemistry
  • Lycopersicon esculentum / genetics*
  • Lycopersicon esculentum / metabolism*
  • Lycopersicon esculentum / ultrastructure
  • Microscopy, Immunoelectron
  • Molecular Sequence Data
  • Mucoproteins / genetics
  • Mucoproteins / isolation & purification*
  • Mucoproteins / metabolism
  • Plant Proteins / genetics
  • Plant Proteins / isolation & purification*
  • Plant Proteins / metabolism
  • Protein Processing, Post-Translational
  • Rabbits


  • DNA, Complementary
  • DNA, Plant
  • Mucoproteins
  • Plant Proteins
  • arabinogalactan proteins