Transcriptional Regulation of the DREB1 Genes under Low Temperature Stress Condition 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. Expressions of the DREB1 genes is induced rapidly by low temperature stress. We analyzed transcriptional regulation of the DREB1 genes under low temperature condition.
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 67-bp region by using the yeast one-hybrid screening. The cDNA encodes a bHLH-type transcription factor named bHLH072. We found that the bHLH072 has an active phytochrome binding (APB) motif in the C-terminal region and functions as a transcriptional repressor in Arabidopsis protoplasts. We are analyzing function of the bHLH072 in the expression of the DREB1 genes under low temperature stress condition using transgenic plants and T-DNA insertion mutants.