Nakashima Kazuo, Fujita Yasunari, Katsura Koji, Maruyama Kyonoshin, Narusaka Yoshihiro, Seki Motoaki, Shinozaki Kazuo, Yamaguchi-Shinozaki Kazuko
Biological Resources Division, Japan International Research Center for Agricultural Sciences, JIRCAS, 1-1 Ohwashi, Tsukuba, 305-8686, Japan.
Plant Mol Biol. 2006 Jan;60(1):51-68. doi: 10.1007/s11103-005-2418-5.
ABA-responsive elements (ABREs) are cis-acting elements and basic leucine zipper (bZIP)-type ABRE-binding proteins (AREBs) are transcriptional activators that function in the expression of RD29B in vegetative tissue of Arabidopsis in response to abscisic acid (ABA) treatment. Dehydration-responsive elements (DREs) function as coupling elements of ABRE in the expression of RD29A in response to ABA. Expression analysis using abi3 and abi5 mutants showed that ABI3 and ABI5 play important roles in the expression of RD29B in seeds. Base-substitution analysis showed that two ABREs function strongly and one ABRE coupled with DRE functions weakly in the expression of RD29A in embryos. In a transient transactivation experiment, ABI3, ABI5 and AREB1 activated transcription of a GUS reporter gene driven by the RD29B promoter strongly but these proteins activated the transcription driven by the RD29A promoter weakly. In 35S::ABI3 Arabidopsis plants, the expression of RD29B was up-regulated strongly, but that of RD29A was up-regulated weakly. These results indicate that the expression of RD29B having ABREs in the promoter is up-regulated strongly by ABI3, whereas that of RD29A having one ABRE coupled with DREs in the promoter is up-regulated weakly by ABI3. We compared the expression of 7000 Arabidopsis genes in response to ABA treatment during germination and in the vegetative growth stage, and that in 35S::ABI3 plants using a full-length cDNA microarray. The expression of ABI3- and/or ABA-responsive genes and cis-elements in the promoters are discussed.
脱落酸应答元件（ABREs）是顺式作用元件，而碱性亮氨酸拉链（bZIP）型ABRE结合蛋白（AREBs）是转录激活因子，它们在拟南芥营养组织中响应脱落酸（ABA）处理时，调控RD29B的表达。脱水应答元件（DREs）在响应ABA时，作为ABRE的偶联元件参与RD29A的表达。利用abi3和abi5突变体进行的表达分析表明，ABI3和ABI5在种子中RD29B的表达中起重要作用。碱基置换分析表明，两个ABRE在胚胎中RD29A的表达中作用强烈，而一个与DRE偶联的ABRE作用较弱。在瞬时反式激活实验中，ABI3、ABI5和AREB1强烈激活由RD29B启动子驱动的GUS报告基因的转录，但这些蛋白对由RD29A启动子驱动的转录激活作用较弱。在35S::ABI拟南芥植株中，RD29B的表达强烈上调，而RD29A的表达上调较弱。这些结果表明，启动子中含有ABREs的RD29B的表达被ABI3强烈上调，而启动子中含有一个与DREs偶联的ABRE的RD29A的表达被ABI3弱上调。我们使用全长cDNA微阵列比较了7000个拟南芥基因在萌发期和营养生长阶段对ABA处理的响应表达，以及在35S::ABI3植株中的表达。讨论了ABI3和/或ABA应答基因的表达以及启动子中的顺式元件。
