Analysis of Transcriptional Regulation of the Cold-Inducible DREB1 Genes in Arabidopsis

Abstract

Arabidopsis transcription factors DREB1s/CBFs specifically interact with a cis-acting element DRE/CRT/LTRE involved in the expression of low-temperature-, drought- and high-salinity-inducible genes. Expression of the DREB1 gene is kept at very low level and regulated by circadian under normal growth conditions, but induced rapidly and significantly by low temperature. We analyzed transcriptional regulation of the DREB1 genes.
Using a GUS reporter gene fused to the DREB1C promoter, we identified a 67-bp region that contains cis-acting elements and isolated a cDNA clone encoding a protein that binds to this region by the yeast one-hybrid screening. The cDNA encoded a bHLH-type transcription factor related to PhyB signaling. We found that this protein binds to the G-box sequence in the promoter region of DREB1C by transient expression assay. We are analyzing function of the protein in the expression of DREB1s using transgenic plants and T-DNA insertion mutants.