The AtCathB3 gene, encoding a cathepsin B-like protease, is expressed during germination of Arabidopsis thaliana and transcriptionally repressed by the basic leucine zipper protein GBF1

Raquel Iglesias-Fernández, Dorothee Wozny, Maite Iriondo-De Hond, Luis Oñate-Sánchez, Pilar Carbonero, Cristina Barrero-Sicilia

Research output: Contribution to journalArticlepeer-review

16 Citations (Scopus)
39 Downloads (Pure)

Abstract

Protein hydrolysis plays an important role during seed germination and post-germination seedling establishment. In Arabidopsis thaliana, cathepsin B-like proteases are encoded by a gene family of three members, but only the AtCathB3 gene is highly induced upon seed germination and at the early post-germination stage. Seeds of a homozygous T-DNA insertion mutant in the AtCathB3 gene have, besides a reduced cathepsin B activity, a slower germination than the wild type. To explore the transcriptional regulation of this gene, we used a combined phylogenetic shadowing approach together with a yeast one-hybrid screening of an arrayed library of approximately 1200 transcription factor open reading frames from Arabidopsis thaliana. We identified a conserved CathB3-element in the promoters of orthologous CathB3 genes within the Brassicaceae species analysed, and, as its DNA-interacting protein, the G-Box Binding Factor1 (GBF1). Transient overexpression of GBF1 together with a PAtCathB3::uidA (β-glucuronidase) construct in tobacco plants revealed a negative effect of GBF1 on expression driven by the AtCathB3 promoter. In stable P35S::GBF1 lines, not only was the expression of the AtCathB3 gene drastically reduced, but a significant slower germination was also observed. In the homozygous knockout mutant for the GBF1 gene, the opposite effect was found. These data indicate that GBF1 is a transcriptional repressor of the AtCathB3 gene and affects the germination kinetics of Arabidopsis thaliana seeds. As AtCathB3 is also expressed during post-germination in the cotyledons, a role for the AtCathB3-like protease in reserve mobilization is also inferred.

Original languageEnglish
Pages (from-to)2009-2021
Number of pages13
JournalJournal of Experimental Botany
Volume65
Issue number8
Early online date5 Mar 2014
DOIs
Publication statusPublished - 1 May 2014

Keywords

  • Arabidopsis thaliana
  • AtCathB3
  • bZIP
  • cathepsin B-like enzymes
  • GBF1
  • phylogenetic shadowing
  • reserve mobilization
  • seed germination
  • transcriptional regulation

Fingerprint

Dive into the research topics of 'The AtCathB3 gene, encoding a cathepsin B-like protease, is expressed during germination of Arabidopsis thaliana and transcriptionally repressed by the basic leucine zipper protein GBF1'. Together they form a unique fingerprint.

Cite this