DREB1

DREB1, also known as C-repeat binding factor (CBF), refers to a subset of plant transcription factors in the AP2/ERF superfamily that regulate cold- and dehydration-responsive gene expression. In Arabidopsis thaliana, three major members have been studied: CBF1/DREB1B, CBF2/DREB1C, and CBF3/DREB1A. These proteins bind specifically to the DRE/CRT element in promoters of stress-responsive genes (the consensus sequence is A/GCCGAC) and activate transcription of downstream targets involved in sheltering cells from freezing and osmotic stress. DREB1 proteins are typically induced rapidly by low temperature, initiating a transcriptional cascade that promotes cold acclimation.

Function and targets: DREB1-regulated genes include a suite of COR (cold-regulated) genes, as well as others involved in osmoprotection, membrane stabilization, and antifreeze activity. The resulting physiological responses help maintain cellular integrity during freezing and dehydration, contributing to enhanced freezing tolerance and, in some contexts, drought and salt tolerance.

Regulation and networks: The cold-induced expression of DREB1 genes is controlled by upstream regulators such as ICE1 (Inducer of CBF Expression 1), a transcription factor that promotes DREB1 transcription. Post-translational and environmental factors modulate this pathway, with cross-talk to other stress pathways including DREB2, which responds more strongly to dehydration and heat. Negative regulators and protein turnover also refine the response.

Evolution and applications: DREB1/CBF genes are present across many angiosperms, often in multigene families with tissue- and condition-specific expression. In crops, ectopic or enhanced expression of DREB1/CBF genes can improve stress tolerance but may incur growth penalties under non-stress conditions, highlighting the need for controlled expression strategies in agricultural engineering.