Arabidopsis AtMYC2 (bHLH) and AtMYB2 (MYB) function as transcriptional activators in abscisic acid signaling
Arabidopsis AtMYC2 (bHLH) and AtMYB2 (MYB) function as transcriptional activators in abscisic acid signaling
复制标题
DOI：
10.1105/tpc.006130
复制
发表时间：
2003-01-01
期刊：
影响因子：
11.6
通讯作者：
Yamaguchi-Shinozaki, K
中科院分区：
文献类型：
--
作者：
Abe, H;Urao, T;Yamaguchi-Shinozaki, K
在拟南芥中，脱水响应基因rd22的诱导是由脱落酸（ABA）介导的。我们之前报道过，rd22启动子区域的MYC和MYB识别位点在干旱和ABA诱导的rd22基因表达中作为顺式作用元件发挥作用。bHLH和MYB相关转录因子rd22BP1（重新命名为AtMYC2）和AtMYB2分别在体外与MYC和MYB识别位点特异性相互作用，并激活由拟南芥叶原生质体中MYC和MYB识别位点驱动的β - 葡萄糖醛酸苷酶报告基因的转录。在此，我们表明过表达AtMYC2和/或AtMYB2 cDNA的转基因植物对ABA具有更高的敏感性。在这些转基因植物中，ABA诱导的rd22和AtADH1基因表达增强。对过表达AtMYC2和AtMYB2 cDNA的转基因植物进行的微阵列分析显示，几种ABA诱导基因在转基因植物中也上调。相比之下，AtMYC2基因的Ds插入突变体对ABA不太敏感，并且ABA诱导的rd22和AtADH1基因表达显著降低。这些结果表明，在植物干旱胁迫下，AtMYC2和AtMYB2蛋白在ABA诱导的基因表达中均作为转录激活因子发挥作用。
In Arabidopsis, the induction of a dehydration-responsive gene, rd22, is mediated by abscisic acid (ABA). We reported previously that MYC and MYB recognition sites in the rd22 promoter region function as cis-acting elements in the drought- and ABA-induced gene expression of rd22. bHLH- and MYB-related transcription factors, rd22BP1 (renamed AtMYC2) and AtMYB2, interact specifically with the MYC and MYB recognition sites, respectively, in vitro and activate the transcription of the beta-glucuronidase reporter gene driven by the MYC and MYB recognition sites in Arabidopsis leaf protoplasts. Here, we show that transgenic plants overexpressing AtMYC2 and/or AtMYB2 cDNAs have higher sensitivity to ABA. The ABA-induced gene expression of rd22 and AtADH1 was enhanced in these transgenic plants. Microarray analysis of the transgenic plants overexpressing both AtMYC2 and AtMYB2 cDNAs revealed that several ABA-inducible genes also are upregulated in the transgenic plants. By contrast, a Ds insertion mutant of the AtMYC2 gene was less sensitive to ABA and showed significantly decreased ABA-induced gene expression of rd22 and AtADH1. These results indicate that both AtMYC2 and AtMYB2 proteins function as transcriptional activators in ABA-inducible gene expression under drought stress in plants.