The role of AHA motifs in the activator function of tomato heat stress transcription factors HsfA1 and HsfA2

Citation
P. Doring et al., The role of AHA motifs in the activator function of tomato heat stress transcription factors HsfA1 and HsfA2, PL CELL, 12(2), 2000, pp. 265-278
Citations number
74
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Plant Sciences","Animal & Plant Sciences
Journal title
PLANT CELL
ISSN journal
1040-4651 → ACNP
Volume
12
Issue
2
Year of publication
2000
Pages
265 - 278
Database
ISI
SICI code
1040-4651(200002)12:2<265:TROAMI>2.0.ZU;2-5
Abstract
Using reporter assays in tobacco protoplasts and yeast, we investigated the function of the acidic C-terminal activation domains of tomato heat stress transcription factors HsfA1 and HsfA2. Both transcription factors contain short, essential peptide motifs with a characteristic pattern of aromatic a nd large hydrophobic amino acid residues embedded in an acidic context (AHA motifs), The prototype is the AHA1 motif of HsfA2, which has the sequence DDIWEELL. Our mutational analysis supports the important role of the aromat ic and large hydrophobic amino acid residues in the core positions of the A HA motifs, The pattern suggests the formation of an amphipathic, negatively charged helix as the putative contact region with components of the basal transcription complex, In support of this concept, proline or positively ch arged residues in or adjacent to the AHA motifs markedly reduce or abolish their activity. Both AHA motifs of HsfA1 and HsfA2 contribute to activator potential, and they can substitute for each other; however, there is eviden ce for sequence and positional specificity.