Plant Molecular Biology

, Volume 60, Issue 5, pp 759–772

The Heat Stress Transcription Factor HsfA2 Serves as a Regulatory Amplifier of a Subset of Genes in the Heat Stress Response in Arabidopsis

  • Franziska Schramm
  • Arnab Ganguli
  • Elke Kiehlmann
  • Gisela Englich
  • Daniela Walch
  • Pascal von Koskull-Döring
Article

DOI: 10.1007/s11103-005-5750-x

Cite this article as:
Schramm, F., Ganguli, A., Kiehlmann, E. et al. Plant Mol Biol (2006) 60: 759. doi:10.1007/s11103-005-5750-x

Abstract

Within the Arabidopsis family of 21 heat stress transcription factors (Hsfs) HsfA2 is the strongest expressed member under heat stress (hs) conditions. Irrespective of the tissue, HsfA2 accumulates under heat stress similarly to other heat stress proteins (Hsps). A SALK T-DNA insertion line with a complete HsfA2-knockout was analyzed with respect to the changes in the transcriptome under heat stress conditions. Ascorbate peroxidase 2 (APX2) was identified as the most affected transcript in addition to several sHsps, individual members of the Hsp70 and Hsp100 family, as well as many transcripts of genes with yet unknown functions. For functional validation, the transcription activation potential of HsfA2 on GUS reporter constructs containing 1 kb upstream promoter sequences of selected target genes were analyzed using transient reporter assays in mesophyll protoplasts. By deletion analysis the promoter region of the strongest affected target gene APX2 was functionally mapped in detail to verify potential HsfA2 binding sites. By electrophoretic mobility shift assays we identified TATA-Box proximal clusters of heat stress elements (HSE) in the promoters of selected target genes as potential HsfA2 binding sites. The results presented here demonstrate that the expression of HsfA2 in Arabidopsis is strictly heat stress-dependent and this transcription factor represents a regulator of a subset of stress response genes in Arabidopsis.

Keywords

Arabidopsis heat stress HsfA2 knockout target genes transcription factor 

Abbreviations

APX2

ascorbate peroxidase 2

CTD

C-terminal domain

DBD

DNA-binding domain

EMSA

electrophoretic mobility shift assay

GUS

β-glucuronidase

hs

heat stress

HSE

heat stress element

Hsf

heat stress transcription factor

Hsp

heat stress protein

ko

knockout

wt

wild type

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Supplementary material

Copyright information

© Springer 2006

Authors and Affiliations

  • Franziska Schramm
    • 1
  • Arnab Ganguli
    • 1
  • Elke Kiehlmann
    • 1
  • Gisela Englich
    • 1
  • Daniela Walch
    • 1
  • Pascal von Koskull-Döring
    • 1
  1. 1.Institute of Molecular Bio Sciences, Biocenter N200/R306Goethe UniversityFrankfurtGermany

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