Previous study has defined DRE (dehydration responsive element) cis acting element and its important role in expressions of Arabidopsis rd29A gene under cold, dehydration and high salt stresses. In order to...Previous study has defined DRE (dehydration responsive element) cis acting element and its important role in expressions of Arabidopsis rd29A gene under cold, dehydration and high salt stresses. In order to clarify the expression mechanism of rd29A gene, we isolated two cDNA clones that encoded DRE binding proteins ( DREB1 and DREB2 ) from cold and drought treated Arabidopsis plants, using DRE cis acting element in the promoter region of rd29A gene and yeast One Hybrid screening method. Experiments showed both DREB1 and DREB2 specifically interacted with DRE cis element. Homologous analysis showed no significant similarity between DREB1 and DREB2 in whole deduced amino acid sequences. However, both DREB1 and DREB2 proteins contained a conserved DNA binding domain (AP2/EREBP domain). Structural analysis of proteins also showed they had a nuclear localization signal (NLS) in their N terminal region and an acidic activation region in their C terminal region. AP2/EREBP domain is composed of 58 amino acids, which presents in a large family of plant genes encoding DNA binding proteins. We analyzed many plant transcription factors containing conserved AP2/EREBP domains. The 14th valine (V) and 19th glutamate (E) in the amino acid sequence of AP2/EREBP domains might be the consensus recognizing and binding to DRE cis element. Northern analysis indicated that DREB1 gene was induced by low temperature, whereas DREB2 gene was induced by dehydration and high salt stresses. Present studies suggest that the expression of rd29A gene under low temperature, dehydration and high salt stresses is regulated by DREB1 and DREB2 transcriptional factors in two separate signal transduction pathways, respectively.展开更多
基金the National Natural Science Foun dation of China! (No .396 70 40 8)
文摘Previous study has defined DRE (dehydration responsive element) cis acting element and its important role in expressions of Arabidopsis rd29A gene under cold, dehydration and high salt stresses. In order to clarify the expression mechanism of rd29A gene, we isolated two cDNA clones that encoded DRE binding proteins ( DREB1 and DREB2 ) from cold and drought treated Arabidopsis plants, using DRE cis acting element in the promoter region of rd29A gene and yeast One Hybrid screening method. Experiments showed both DREB1 and DREB2 specifically interacted with DRE cis element. Homologous analysis showed no significant similarity between DREB1 and DREB2 in whole deduced amino acid sequences. However, both DREB1 and DREB2 proteins contained a conserved DNA binding domain (AP2/EREBP domain). Structural analysis of proteins also showed they had a nuclear localization signal (NLS) in their N terminal region and an acidic activation region in their C terminal region. AP2/EREBP domain is composed of 58 amino acids, which presents in a large family of plant genes encoding DNA binding proteins. We analyzed many plant transcription factors containing conserved AP2/EREBP domains. The 14th valine (V) and 19th glutamate (E) in the amino acid sequence of AP2/EREBP domains might be the consensus recognizing and binding to DRE cis element. Northern analysis indicated that DREB1 gene was induced by low temperature, whereas DREB2 gene was induced by dehydration and high salt stresses. Present studies suggest that the expression of rd29A gene under low temperature, dehydration and high salt stresses is regulated by DREB1 and DREB2 transcriptional factors in two separate signal transduction pathways, respectively.
