title: Differential expression of AtXTH17, AtXTH18, AtXTH19 and AtXTH20 genes in Arabidopsis roots. Physiological roles in specification in cell wall construction.
abstract: Xyloglucan endotransglucosylase/hydrolases (XTHs) are a class of enzymes that are capable of splitting and reconnecting xyloglucan molecules, and are implicated in the construction and restructuring of the cellulose/xyloglucan framework. Thirty-three members of the XTH gene family are found in the genome of Arabidopsis thaliana, but their roles remain unclear. Here, we describe the tissue-specific and growth stage-dependent expression profiles of promoter::GUS fusion constructs for four Arabidopsis XTH genes, AtXTH17, AtXTH18, AtXTH19 and AtXTH20, which are phylogenetically closely related to one another. AtXTH17 and AtXTH18 were expressed in all cell types in the elongating and differentiating region of the root, while AtXTH19 was expressed in the apical dividing and elongating regions, as well as in the differentiation zone, and was up-regulated by auxin. In contrast, AtXTH20 was expressed specifically in vascular tissues in the basal mature region of the root. This expression analysis also disclosed cis-regulatory sequences that are conserved among the four genes, and are responsible for the root-specific expression profile. These results indicate that the four XTH genes, which were generated by gene duplication, have diversified their expression profile within the root in such a way as to take responsibility for particular physiological roles in the cell wall dynamics.
authors.affiliation: University of Antwerp, Department of Biology, Plant Physiology and Morphology, Universiteitsplein 1, B-2610 Wilrijk, Belgium.
authors.forename: Kris
authors.initials: K
authors.lastname: Vissenberg
authors.forename: Mika
authors.initials: M
authors.lastname: Oyama
authors.forename: Yasue
authors.initials: Y
authors.lastname: Osato
authors.forename: Ryusuke
authors.initials: R
authors.lastname: Yokoyama
authors.forename: Jean-Pierre
authors.initials: JP
authors.lastname: Verbelen
authors.forename: Kazuhiko
authors.initials: K
authors.lastname: Nishitani
mesh_terms: D017360:Arabidopsis / Q000201:enzymology* / Q000235:genetics* / Q000254:growth & development; D001483:Base Sequence; D002473:Cell Wall / Q000201:enzymology; D017124:Conserved Sequence; D018744:DNA, Plant / Q000235:genetics; D015971:Gene Expression Regulation, Enzymologic; D018506:Gene Expression Regulation, Plant; D017343:Genes, Plant; D016695:Glycosyltransferases / Q000235:genetics* / Q000378:metabolism*; D008969:Molecular Sequence Data; D005810:Multigene Family; D018517:Plant Roots / Q000201:enzymology; D030821:Plants, Genetically Modified; D011401:Promoter Regions, Genetic; D012689:Sequence Homology, Nucleic Acid
chemical_list: D018744:DNA, Plant; D016695:Glycosyltransferases; C473049:xyloglucan - xyloglucosyltransferase