Abstract：Five EST (expressed sequence tag) sequences were obtained in NCBI web BLAST according to the AP2 domain sequence of DREB(dehydration-responsive binding protein)1a gene from Arabidopsis. Specific primers were designed based on the EST sequences, and two DREB-like genes were amplified from tobacco (Nicotiana benthamiana) cDNA by PCR， and named NbDREB1 and NbDREB2 respectively and could be expressed in Escherichia coli. Comparing with other dehydration-responsive element binding related protein found that NbDREB1 and NbDREB2 possessed typical structural characteristics of A type of EREBP subgroup in AP2/EDREBP transcription factor family . The yeast one-hybrid (expression vector YepGap) showed that the two genes had no active function. Anti-activator yeast one-hybrid (expression vector pGADT7containning GAL4 domain) assay showed that NbDREB1 could bind to DRE cis-element in yeast, but NbDREB2 could not. The difference of AP2 domain between NbDREB1 and NbDREB2 was only in the 2nd and 49th amino acid, which was Y and K in NbDREB1 and N and R in NbDREB2.
