PlantRegMap/PlantTFDB v5.0
Plant Transcription Factor Database
Medicago truncatula
HSF Family
Species TF ID Description
Medtr0020s0020.1HSF family protein
Medtr1g061170.3HSF family protein
Medtr1g071360.1HSF family protein
Medtr1g071360.2HSF family protein
Medtr1g100777.1HSF family protein
Medtr1g102860.1HSF family protein
Medtr2g017890.1HSF family protein
Medtr2g100670.1HSF family protein
Medtr2g100670.2HSF family protein
Medtr2g100680.1HSF family protein
Medtr3g101870.1HSF family protein
Medtr3g104550.1HSF family protein
Medtr3g104550.2HSF family protein
Medtr3g104550.3HSF family protein
Medtr4g045757.1HSF family protein
Medtr4g077970.1HSF family protein
Medtr4g077970.3HSF family protein
Medtr4g088900.1HSF family protein
Medtr4g126070.1HSF family protein
Medtr5g010680.1HSF family protein
Medtr5g010680.2HSF family protein
Medtr5g010680.3HSF family protein
Medtr5g010680.4HSF family protein
Medtr5g017470.1HSF family protein
Medtr5g029680.1HSF family protein
Medtr5g029680.2HSF family protein
Medtr5g047190.1HSF family protein
Medtr5g089170.1HSF family protein
Medtr6g043060.1HSF family protein
Medtr6g086805.1HSF family protein
Medtr7g091370.1HSF family protein
Medtr7g095680.1HSF family protein
Medtr8g083100.1HSF family protein
Medtr8g087540.1HSF family protein
Medtr8g105780.1HSF family protein
Medtr8g105780.2HSF 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