Abstract
A cDNA encoding a DRE (dehydration-responsive element)-binding protein, DREB1A have been isolated using yeast one-hybrid screenig. The DREB1A-transcript-accumulates specifically under low-temperature condition. We have repoted that overexpression of DREB1A transgenic Arabidopsis activated expression of target stress-inducible genes and resulted in improved drought and freezing tolerance. To detect target stress-inducible genes of DREB1A, we performed microarray analysis using two different systems, our 7000 full-length cDNA microarray and 8000 Affymetrix GeneChip, and compared results obtained with the two systems. We identified the direct target genes for DREB1A/CBF3 by 3 criteria as follows after northern blot analysis. (1) Increase level of transcripts in the 35S:DREB1A transgenic-plants under control condition. (2) Significantly increased transcripts from 2 to 10 hours after low temperature treatment. (3) Existence of DRE core motif in the promoter regions. We discuss the functions of the DREB1A target genes and the gene expression network controlled by DREB1A.
