Maize DRE-binding proteins DBF1 and DBF2 are involved in rab17 regulation through the drought-responsive element in an ABA-dependent pathway
Maize DRE-binding proteins DBF1 and DBF2 are involved in rab17 regulation through the drought-responsive element in an ABA-dependent pathway
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DOI：
10.1046/j.1365-313x.2002.01325.x
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发表时间：
2002-06-01
期刊：
影响因子：
7.2
通讯作者：
Pagès, M
中科院分区：
文献类型：
--
作者：
Kizis, D;Pagès, M
玉米脱落酸响应基因rab17在胚发生后期表达，受ABA和干燥诱导，在胚和营养组织中表达。ABRE和DRE顺式元件参与ABA和干旱对该基因的调控。通过酵母单杂交筛选，我们分离出了两个编码AP2/EREBP转录因子家族成员的新的dre结合蛋白DBF1和DBF2的cdna。对DBF1 mRNA积累谱的分析表明，DBF1在玉米胚发生过程中以及幼苗脱水、NaCl和ABA处理后均有诱导作用，而DBF2 mRNA不受诱导。电泳迁移位移法分析了dbf的dna结合偏好，结果表明，DBF1和DBF2都与野生型DRE2元件结合，而不是与DRE2突变体或DRE1元件结合，后者只有一个核苷酸的差异。颗粒轰击的转激活活性表明，DBF1作为ABA对rab17启动子dre2依赖性转录的激活因子，而DBF2过表达不仅抑制了基础启动子活性，还抑制了ABA的作用。这些结果表明，ABA在调控DBF活性中发挥作用，并提示存在ABA依赖通路通过C-repeat/DRE元件调控基因。
The abscisic acid-responsive gene rab17 of maize is expressed during late embryogenesis, and is induced by ABA and desiccation in embryo and vegetative tissues. ABRE and DRE cis -elements are involved in regulation of the gene by ABA and drought. Using yeast one-hybrid screening, we isolated two cDNAs encoding two new DRE-binding proteins, designated DBF1 and DBF2, that are members of the AP2/EREBP transcription factor family. Analysis of mRNA accumulation profiles showed that DBF1 is induced during maize embryogenesis and after desiccation, NaCl and ABA treatments in plant seedlings, whereas the DBF2 mRNA is not induced. DNA-binding preferences of DBFs were analysed by electrophoretic mobility shift assays, and showed that both DBF1 and DBF2 bound to the wild-type DRE2 element, but not to the DRE2 mutant or to the DRE1 element which differs only in a single nucleotide. Transactivation activity using particle bombardment showed that DBF1 functioned as activator of DRE2-dependent transcription of rab17 promoter by ABA, whereas DBF2 overexpression had a repression action downregulating not only the basal promoter activity, but also the ABA effect. These results show that ABA plays a role in the regulation of DBF activity, and suggests the existence of an ABA-dependent pathway for the regulation of genes through the C-repeat/DRE element.