title: A novel extracellular matrix protein from tomato associated with lignified secondary cell walls.
abstract: A cDNA clone representing a novel cell wall protein was isolated from a tomato cDNA library. The deduced amino acid sequence shows that the encoded protein is very small (88 amino acids), contains an N-terminal hydrophobic signal peptide, and is enriched in lysine and tyrosine. We have designated this protein TLRP for tyrosine- and lysine-rich protein. RNA gel blot hybridization identified TLRP transcripts constitutively present in roots, stems, and leaves from tomato plants. The encoded protein seems to be highly insolubilized in the cell wall, and we present evidence that this protein is specifically localized in the modified secondary cell walls of the xylem and in cells of the sclerenchyma. In addition, the protein is localized in the protective periderm layer of the growing root. The highly localized deposition in cells destined to give support and protection to the plant indicates that this cell wall protein alone and/or in collaboration with other cell wall structural proteins may have a specialized structural function by mechanically strengthening the walls.
authors.affiliation: Instituto de Biología Molecular y Celular de Plantas (IBMCP), Universidad Politécnica, Valencia, Spain.
authors.forename: C
authors.initials: C
authors.lastname: Domingo
authors.forename: M D
authors.initials: MD
authors.lastname: Gómez
authors.forename: L
authors.initials: L
authors.lastname: Cañas
authors.forename: J
authors.initials: J
authors.lastname: Hernández-Yago
authors.forename: V
authors.initials: V
authors.lastname: Conejero
authors.forename: P
authors.initials: P
authors.lastname: Vera
mesh_terms: D000595:Amino Acid Sequence; D001483:Base Sequence; D002451:Cell Compartmentation; D002454:Cell Differentiation; D002473:Cell Wall / Q000737:chemistry*; D018076:DNA, Complementary / Q000235:genetics; D016326:Extracellular Matrix Proteins / Q000235:genetics* / Q000302:isolation & purification; D018506:Gene Expression Regulation, Plant; D017343:Genes, Plant / Q000235:genetics*; D007150:Immunohistochemistry; D008031:Lignin; D018551:Solanum lycopersicum / Q000235:genetics / Q000378:metabolism* / Q000648:ultrastructure; D008969:Molecular Sequence Data; D010940:Plant Proteins / Q000235:genetics* / Q000302:isolation & purification; D018547:Plant Stems / Q000033:anatomy & histology; D012333:RNA, Messenger / Q000235:genetics; D017422:Sequence Analysis, DNA; D017386:Sequence Homology, Amino Acid; D012995:Solubility
chemical_list: D018076:DNA, Complementary; D016326:Extracellular Matrix Proteins; D010940:Plant Proteins; D012333:RNA, Messenger; C089913:TLRP protein, Lycopersicon esculentum; D008031:Lignin