Abstract
To elucidate the signal transduction pathways between the initial drought / high-salinity-stress signal and gene expressions in Arabidopsis, we have analyzed the regulation of gene expression of rd29B in vegetative tissue. We have shown that ABA Responsive Elements (ABRE) play a crucial role in the dehydration-responsive induction of rd29B as regulatory cis-elements, and that bZIP transcription factors, ABA Responsive Element Binding Proteins (AREB), function as transcriptional activators in the ABA-inducible expression of rd29B.
In this study, to identify domains of the AREB1 protein involved in ABA-inducible transcriptional activation of rd29B, we analyzed trans-activation activity of AREB1 using a transient assay of Arabidopsis protoplasts. The analysis of mutants in this assay revealed that the N-terminal region can function as a transcriptional activation domain. Furthermore, the results of collective analyses suggested that conformational change in AREB1 via ABA-induced modification is required for the gene expression of rd29B.
