Extensin-a major cell wall glycoprotein

Wilson, Leslie; Fry, John C.

doi:10.1111/j.1365-3040.1986.tb01737.x

Cited by 51 publications

(65 citation statements)

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“…3) While the structure and function of extensin in cell walls were well known 17,22) and have been established, those of GRP have not 'been established. Recently, the structures of some plant genes encoding GRPs have been reported.1.…”

Section: Discussionmentioning

confidence: 99%

Purification and Characterization of a Glycine-rich Protein from the Aleurone Layer of Soybean Seeds

Matsui

Toyosawa

Fukuda

1995

Bioscience, Biotechnology, and Biochemistry

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Section: Discussionmentioning

confidence: 99%

Purification and Characterization of a Glycine-rich Protein from the Aleurone Layer of Soybean Seeds

Matsui

Toyosawa

Fukuda

1995

Bioscience, Biotechnology, and Biochemistry

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“…Extensins form an abundant group of cell wall structural proteins belonging to the family of Hyp-rich glycoproteins. They are defined by the presence of the repeated pentapeptide Ser(Hyp) 4 (Kieliszewski et al, 1990;Kieliszewski and Lamport, 1994), where most Hyp and Ser residues are glycosylated (Wilson and Fry, 1986). One proposed function of extensins is to reinforce the polysaccharidic structure of the wall by cross-linking to each other and/or other cell wall components.…”

mentioning

confidence: 99%

Whole-Genome Comparison of Leucine-Rich Repeat Extensins in Arabidopsis and Rice. A Conserved Family of Cell Wall Proteins Form a Vegetative and a Reproductive Clade,

et al. 2003

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We have searched the Arabidopsis and rice (Oryza sativa) genomes for homologs of LRX1, an Arabidopsis gene encoding a novel type of cell wall protein containing a leucine-rich repeat (LRR) and an extensin domain. Eleven and eight LRX (LRR/EXTENSIN) genes have been identified in these two plant species, respectively. The LRX gene family encodes proteins characterized by a short N-terminal domain, a domain with 10 LRRs, a cysteine-rich motif, and a variable C-terminal extensin-like domain. Phylogenetic analysis performed on the conserved domains indicates the existence of two major clades of LRX proteins that arose before the eudicot/monocot divergence and then diversified independently in each lineage. In Arabidopsis, gene expression studies by northern hybridization and promoter::uidA fusions showed that the two phylogenetic clades represent a specialization into "reproductive" and "vegetative" LRXs. The four Arabidopsis genes of the "reproductive" clade are specifically expressed in pollen, whereas the seven "vegetative" genes are predominantly expressed in various sporophytic tissues. This separation into two expression classes is also supported by previous studies on maize (Zea mays) and tomato (Lycopersicon esculentum) LRX homologs and by information on available rice ESTs. The strong conservation of the amino acids responsible for the putative recognition specificity of the LRR domain throughout the family suggests that the LRX proteins interact with similar ligands.With the completion of the Arabidopsis genome sequence, it became clear that many Arabidopsis genes are members of multigene families. Although this had already been suggested by the analysis of expressed sequence tag (EST) databases and by classical gene searches, the availability of the full gene set of a plant provides the unique opportunity to get a complete inventory of all the members of a gene family. Among the 25,500 genes predicted in the Arabidopsis genome, 65% are members of a multigene family and 37% belong to families of more than five members (Arabidopsis Genome Initiative, 2000). Although the predicted total gene number of Arabidopsis is significantly larger than that of other sequenced multicellular eukaryotes such as Caenorhabditis elegans (19,000; C. elegans Sequencing Consortium, 1998) or Drosophila melanogaster (13,600; Adams et al., 2000), the absolute number of gene families and singletons (11,601 in Arabidopsis) is comparable in all these organisms (Arabidopsis Genome Initiative, 2000). This indicates that frequent gene duplications and consequently large gene families are a distinctive feature of the Arabidopsis genome, and possibly of all plant genomes. With the recent publication of a high-quality draft from two different subspecies, rice (Oryza sativa) is the second plant whose genome can be comprehensively investigated. Depending on the stringency applied in gene prediction, the rice genome contains between 32,277 and 61,668 genes (Goff et al., 2002;Yu et al., 2002). With 77% of the genes distributed in about 15,000 m...

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“…This insolubility hindered the study ofextensin until the isolation ofsalt-soluble extensin precursors (monomers ofMr about 9 x 104) from cell suspension cultures (21) and wounded carrot disks (4,23), which has enabled progress on extensin's structure and properties to be made in recent years (see review, ref. 26). The mechanism by which extensin monomers become covalently bound in ' K. J.…”

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Solubilization of Covalently Bound Extensin from Capsicum Cell Walls

Biggs¹,

Fry²

1990

Plant Physiol.

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Acidified sodium chlorite cleaves isodityrosine and solubilizes covalently bound hydroxyproline-rich material from cell walls. This has been taken as evidence that isodityrosine acts as a cross-link holding the hydroxyproline-rich glycoprotein extensin in the cell wall. However, acidified chlorite was found to cleave peptide bonds in salt-soluble extensin and in bovine serum albumin (BSA). This invalidates the use of conventional acidified chlorite treatment to provide evidence for isodityrosine crosslinks. The rafto of BSA:chlorite was important in determining peptidyl cleavage. At a ratio of 0.75:1.00 (mole amino acid residues/mole chlorite), or higher, peptidyl cleavage was not detected. Furthermore, in samples where a low concentration of radioactive extensin was present, BSA substantially protected the peptide bonds of the extensin against peptidyl cleavage during treatment with acidified chlorite, while not preventing the cleavage of isodityrosine. Therefore, acidified sodium chlorite plus BSA was a more specific reagent for the cleavage of isodityrosine than was acidified chlorite alone. This modified treatment solubilized in intact form the 'covalently bound' extensin from cell walls of Capsicum frutescens (chili pepper) suspension cultures, providing new evidence compatible with the view that extensin molecules are held in the cell wall by isodityrosine cross-links.Plant cell walls contain the HRGP2 called extensin, which forms an insoluble and perhaps structurally important network (13). Mature extensin is insoluble in many of the usual protein extractants such as detergents (8), salts (24), dilute acids and alkalis (14), PAW (present paper), and anhydrous hydrogen fluoride (16) and is therefore thought to be covalently bound within the cell wall. This insolubility hindered the study ofextensin until the isolation ofsalt-soluble extensin precursors (monomers ofMr about 9 x 104) from cell suspension cultures (21) and wounded carrot disks (4, 23), which has enabled progress on extensin's structure and properties to be made in recent years (see review, ref. 26 the wall network is unknown, but the isolation ofthe phenolic amino acid isodityrosine (an oxidatively coupled dimer of tyrosine units linked by a diphenylether bridge) from cell wall hydrolysates (8) led to the suggestion that isodityrosine could form inter-polypeptide cross-links between extensin molecules (2, 9).Studies on isolated carrot root disks (4,5) showed that newly synthesized extensin monomers were secreted from the cytoplasm and were slowly insolubilized in the walls. Insolubilization was accompanied by isodityrosine formation, but it was not proven that the isodityrosine formed was responsible for insolubilization.In another study HRGP was solubilized from bean cell walls by treatment with acidified chlorite (17,19,20), a reagent that is extensively used for delignification and known to split phenolic linkages (6). In addition to an ability to solubilize HRGP, acidified chlorite has been shown to degrade pure isodityrosine (8,...

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Extensin-a major cell wall glycoprotein

Cited by 51 publications

References 106 publications

Purification and Characterization of a Glycine-rich Protein from the Aleurone Layer of Soybean Seeds

Purification and Characterization of a Glycine-rich Protein from the Aleurone Layer of Soybean Seeds

Whole-Genome Comparison of Leucine-Rich Repeat Extensins in Arabidopsis and Rice. A Conserved Family of Cell Wall Proteins Form a Vegetative and a Reproductive Clade,

Solubilization of Covalently Bound Extensin from Capsicum Cell Walls

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