Journal Article

A Xylanase, AtXyn1, is Predominantly Expressed in Vascular Bundles, and Four Putative Xylanase Genes were Identified in the <i>Arabidopsis thaliana</i> Genome

Masashi Suzuki, Atsushi Kato, Noriko Nagata and Yoshibumi Komeda

in Plant and Cell Physiology

Published on behalf of Japanese Society of Plant Physiologists

Volume 43, issue 7, pages 759-767
Published in print July 2002 | ISSN: 0032-0781
Published online July 2002 | e-ISSN: 1471-9053 | DOI: http://dx.doi.org/10.1093/pcp/pcf088
A Xylanase, AtXyn1, is Predominantly Expressed in Vascular Bundles, and Four Putative Xylanase Genes were Identified in the Arabidopsis thaliana Genome

More Like This

Show all results sharing these subjects:

  • Biochemistry
  • Molecular and Cell Biology
  • Plant Sciences and Forestry

GO

Show Summary Details

Preview

The cDNA clone RXF12, which encodes a xylanase (EC 3.2.1.8), was isolated from Arabidopsis thaliana. The C-terminal half of the amino acid sequence of the deduced protein, named AtXyn1, showed similarity with the catalytic domain of barley xylanase X-1. The N-terminal half of AtXyn1 also contained three regions with sequences similar to cellulose-binding domains (CBDs). A xylanase assay revealed that transgenic A. thaliana plants expressing exogenous AtXyn1 fused with enhanced green fluorescent protein (EGFP) possessed approximately twice as much xylanase activity as wild-type plants. Observation by fluorescence microscopy of transgenic A. thaliana plants expressing a fusion protein of AtXyn1 and EGFP suggested that AtXyn1 is a cell wall protein. Analysis of the localization of β-glucuronidase (GUS) activity in transgenic A. thaliana plants containing a chimeric gene with the upstream sequence of the AtXyn1 gene and the GUS gene demonstrated that the AtXyn1 gene is predominantly expressed in vascular bundles, but not in vessel cells. These data suggest that AtXyn1 is involved in the secondary cell wall metabolism of vascular bundle cells. A database search revealed that four putative xylanase genes exist in the A. thaliana genome, besides the AtXyn1 gene. Of these, two also contain several regions with sequences similar to CBDs in their N-terminal regions. Comparison of the amino acid sequences of the five xylanases suggests a possible process for their molecular evolution.

Keywords: Keywords: Arabidopsis thaliana — cDNA — Secondary cell wall — Vascular bundles — Xylanase (EC 3.2.1.8).; Abbreviations: CBD, cellulose-binding domain; EGFP, enhanced green fluorescent protein; GUS, β-glucuronidase; TSD, thermostabilizing domain; DTT, dithiothreitol; RBB-xylan, Remazole Brilliant Blue-Xylan.

Journal Article.  6243 words.  Illustrated.

Subjects: Biochemistry ; Molecular and Cell Biology ; Plant Sciences and Forestry

Full text: subscription required

How to subscribe Recommend to my Librarian

Users without a subscription are not able to see the full content. Please, subscribe or login to access all content.