Redox-mediated Mechanisms Regulate DNA Binding Activity of the G-group of Basic Region Leucine Zipper (bZIP) Transcription Factors in Arabidopsis
Redox-mediated Mechanisms Regulate DNA Binding Activity of the G-group of Basic Region Leucine Zipper (bZIP) Transcription Factors in Arabidopsis
复制标题
DOI：
10.1074/jbc.m112.361394
复制
发表时间：
2012-08-10
影响因子：
4.8
通讯作者：
Strand, Asa
中科院分区：
文献类型：
--
作者：
Shaikhali, Jehad;Noren, Louise;Strand, Asa
在其启动子中含有G-box的植物基因对各种环境刺激有反应。转录组数据的生物信息学分析显示，G-box元件显着富集在高光响应基因的启动子。从高光处理的拟南芥植物的核提取物中，我们确定了AtbZIP 16转录因子作为与含G-box启动子片段的捕光叶绿素a/b结合蛋白2.4（LHCB2.4）结合的组分。AtbZIP 16属于拟南芥碱性区亮氨酸拉链（basic region leucine zipper，bZIP）类型的G-组转录因子。虽然AtbZIP 16及其同源物AtbZIP 68和AtGBF 1结合G盒，但它们不结合G盒回文序列的突变半位点。此外，在酵母双杂交系统中，AtbZIP 16与AtbZIP 68和AtGBF 1相互作用。一个保守的半胱氨酸残基被证明是必要的氧化还原调节和增强的DNA结合活性在所有三种蛋白质。此外，过表达野生型bZIP 16和bZIP 68和GBF 1的T-DNA插入突变体的转基因拟南芥系表现出LHCB 2.4表达的调节受损。最后，bZIP 16突变的Cys变体的过表达系为Cys 330在基因表达的氧化还原调节中的生物学意义提供了支持。因此，我们的研究结果表明，环境诱导的氧化还原状态的变化调节的G-组的bZIP转录因子的成员的活动。
Plant genes that contain the G-box in their promoters are responsive to a variety of environmental stimuli. Bioinformatics analysis of transcriptome data revealed that the G-box element is significantly enriched in promoters of high light-responsive genes. From nuclear extracts of high light-treated Arabidopsis plants, we identified the AtbZIP16 transcription factor as a component binding to the G-box-containing promoter fragment of light-harvesting chlorophyll a/b-binding protein2.4 (LHCB2.4). AtbZIP16 belongs to the G-group of Arabidopsis basic region leucine zipper (bZIP) type transcription factors. Although AtbZIP16 and its close homologues AtbZIP68 and AtGBF1 bind the G-box, they do not bind the mutated half-sites of the G-box palindrome. In addition, AtbZIP16 interacts with AtbZIP68 and AtGBF1 in the yeast two-hybrid system. A conserved Cys residue was shown to be necessary for redox regulation and enhancement of DNA binding activity in all three proteins. Furthermore, transgenic Arabidopsis lines overexpressing the wild type version of bZIP16 and T-DNA insertion mutants for bZIP68 and GBF1 demonstrated impaired regulation of LHCB2.4 expression. Finally, overexpression lines for the mutated Cys variant of bZIP16 provided support for the biological significance of Cys330 in redox regulation of gene expression. Thus, our results suggest that environmentally induced changes in the redox state regulate the activity of members of the G-group of bZIP transcription factors.