Nuclear Activity of ROXY1, a Glutaredoxin Interacting with TGA Factors, Is Required for Petal Development in Arabidopsis thaliana
Nuclear Activity of ROXY1, a Glutaredoxin Interacting with TGA Factors, Is Required for Petal Development in Arabidopsis thaliana
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DOI：
10.1105/tpc.108.064477
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发表时间：
2009-02-01
期刊：
影响因子：
11.6
通讯作者：
Zachgo, Sabine
中科院分区：
文献类型：
--
作者：
Li, Shutian;Lauri, Andrea;Zachgo, Sabine
谷氧还蛋白（GRX）迄今为止主要与参与应激反应的氧化还原调节过程有关。然而，ROXY 1，编码一个GRX，最近已被证明可以调节拟南芥花瓣原基的启动和进一步的花瓣形态建成。ROXY 1属于陆地植物特有的一类GRX，具有CC型活性位点基序，与普遍存在的CPYC和CGFS GRX不同。花椰菜花叶病毒35 S启动子驱动的黄色荧光蛋白-ROXY 1融合基因的表达研究揭示了ROXY 1的核质分布。我们证明，ROXY 1的核定位是必不可少的，因此它的活性在花发育中至关重要。酵母双杂交筛选确定TGA转录因子相互作用的蛋白质，这是证实了双分子荧光互补实验显示它们在植物核相互作用。ROXY 1和TGA基因在花发育过程中的重叠表达模式表明，ROXY 1/TGA蛋白相互作用可以在体内发生，并支持它们在花瓣发育中的生物学相关性。ROXY 1的缺失分析证明了C末端对于其功能和介导ROXY 1/TGA蛋白相互作用的重要性。roxy 1 -2泛双突变体和工程嵌合阻遏突变体的PERIANTHIA（PAN），花TGA基因的表型分析，支持ROXY 1在花瓣发育中的双重作用。总之，我们的研究结果表明，ROXY 1蛋白在细胞核中的功能，可能是通过修改PAN postertilationally，从而调节其在花瓣原基启动的活动。此外，ROXY 1影响后期花瓣形态发生，可能是通过调节其他TGA因子，这些因子可能在第二轮器官分化过程中起冗余作用。
Glutaredoxins (GRXs) have thus far been associated mainly withredox-regulated processes participating in stress responses. However, ROXY1, encoding a GRX, has recently been shown to regulate petal primorida initiation and further petal morphogenesis in Arabidopsis thaliana. ROXY1 belongs to a land plant-specific class of GRXs that has a CC-type active site motif, which deviates from ubiquitously occurring CPYC and CGFS GRXs. Expression studies of yellow fluorescent protein-ROXY1 fusion genes driven by the cauliflower mosaic virus 35S promoter reveal a nucleocytoplasmic distribution of ROXY1. We demonstrate that nuclear localization of ROXY1 is indispensable and thus crucial for its activity in flower development. Yeast two-hybrid screens identified TGA transcription factors as interacting proteins, which was confirmed by bimolecular fluorescence complementation experiments showing their nuclear interaction in planta. Overlapping expression patterns of ROXY1 and TGA genes during flower development demonstrate that ROXY1/TGA protein interactions can occur in vivo and support their biological relevance in petal development. Deletion analysis of ROXY1 demonstrates the importance of the C terminus for its functionality and for mediating ROXY1/TGA protein interactions. Phenotypic analysis of the roxy1-2 pan double mutant and an engineered chimeric repressor mutant from PERIANTHIA ( PAN), a floral TGA gene, supports a dual role of ROXY1 in petal development. Together, our results show that the ROXY1 protein functions in the nucleus, likely by modifying PAN posttranslationally and thereby regulating its activity in petal primordia initiation. Additionally, ROXY1 affects later petal morphogenesis, probably by modulating other TGA factors that might act redundantly during differentiation of second whorl organs.