Plant Transcription Factor Database
Previous version: v3.0
Sphagnum fallax
HSF Family
Species TF ID Description
Sphfalx0003s0024.1.pHSF family protein
Sphfalx0003s0024.2.pHSF family protein
Sphfalx0004s0025.1.pHSF family protein
Sphfalx0004s0025.2.pHSF family protein
Sphfalx0008s0027.1.pHSF family protein
Sphfalx0008s0027.2.pHSF family protein
Sphfalx0032s0107.1.pHSF family protein
Sphfalx0032s0107.2.pHSF family protein
Sphfalx0046s0041.1.pHSF family protein
Sphfalx0067s0105.1.pHSF family protein
Sphfalx0067s0105.2.pHSF family protein
Sphfalx0080s0077.1.pHSF family protein
Sphfalx0086s0033.1.pHSF family protein
Sphfalx0086s0033.2.pHSF family protein
Sphfalx0148s0009.1.pHSF family protein
Sphfalx0305s0001.1.pHSF family protein
HSF Family Introduction

Heat stress transcription factors (Hsfs) are the major regulators of the plant heat stress (hs) response. Sequencing of the Arabidopsis genome revealed the existence of 21 open-reading frames (ORFs) encoding putative Hsfs assigned to classes A-C. Here we present results of a functional genomics approach to the Arabidopsis Hsf family focused on the analysis of their C-terminal domains (CTDs) harboring conserved modules for their function as transcription factors and their intracellular localization. Using reporter assays in tobacco protoplasts and yeast as well as glutathione-S-transferase (GST) pull-down assays, we demonstrate that short peptide motifs enriched with aromatic and large hydrophobic amino acid (aa) residues embedded in an acidic surrounding (AHA motifs) are essential for transcriptional activity of class A Hsfs. In contrast to this, class B and C Hsfs lack AHA motifs and have no activator function on their own. We also provide evidence for the function of a leucine (Leu)-rich region centered around a conserved QMGΦL motif at the very C-terminus as a nuclear export signal (NES) of class A Hsfs. Sequence comparison indicates that the combination of a C-terminal AHA motif with the consensus sequence FWxxF/L,F/I/L as well as the adjacent NES represents a signature domain for plant class A Hsfs, which allowed to identify more than 60 new Hsfs from the expressed sequence tag (EST) database.

Kotak S, Port M, Ganguli A, Bicker F, von Koskull-Doring P.
Characterization of C-terminal domains of Arabidopsis heat stress transcription factors (Hsfs) and identification of a new signature combination of plant class A Hsfs with AHA and NES motifs essential for activator function and intracellular localization.
Plant J, 2004. 39(1): p. 98-112.
PMID: 15200645