The α-helical D1 domain of the tobacco bZIP transcription factor BZI-1 interacts with the ankyrin-repeat protein ANK1 and is important for BZI-1 function, both in auxin signaling and pathogen response
The α-helical D1 domain of the tobacco bZIP transcription factor BZI-1 interacts with the ankyrin-repeat protein ANK1 and is important for BZI-1 function, both in auxin signaling and pathogen response
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DOI：
10.1074/jbc.m210292200
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发表时间：
2003-03-07
影响因子：
4.8
通讯作者：
Dröge-Laser, W
中科院分区：
文献类型：
--
作者：
Kuhlmann, M;Horvay, K;Dröge-Laser, W
烟草bZIP转录因子BZI-1参与生长素介导的生长反应和病原菌防御。表达显性负性BZI-1-Deltan衍生物的转基因植株表现出营养生长的改变。特别是生长素诱导的生根和烟草花叶病毒诱导的过敏性反应损伤的形成受到影响。在不同植物中描述的BZI-1相关蛋白具有保守的结构域D1、D2、BD和D4。为了确定与转录因子功能相关的BZI-1结构域，我们在转基因植物中表达了BZI-1缺失衍生物。BZI-1-Deltan功能域在植物中起关键作用的是D1区或BD域。基本的BD结构域是BZI-1的DNA结合的中介。酵母双杂交和体外结合研究揭示了Ankyrin-Repeat蛋白ANK1，它与编码D1结构域的部分BZI-1蛋白(氨基酸73-222)特异地相互作用。ANK1不与DNA结合，也不作为BZI-1介导的转录的共激活因子。此外，绿色荧光蛋白定位研究表明，ANK1主要作用于胞浆内。转录分析表明，ANK1普遍表达，但在病原体攻击后，转录短暂下调。沿着这些路线，拟南芥中的ANK1同源蛋白已被报道在病原菌防御中发挥功能。因此，我们认为D1域作为ANK1的相互作用表面，似乎调节BZI-1在生长素信号和病原体反应中的功能。
The tobacco (Nicotiana tabacum) bZIP transcription factor BZI-1 is involved in auxin-mediated growth responses and in establishing pathogen defenses. Transgenic plants expressing a dominant-negative BZI-1-DeltaN derivative, which lacks the N-terminal activation domain, showed altered vegetative growth. In particular auxin-induced rooting and formation of tobacco mosaic virus-induced hypersensitive response lesions are affected. BZI-1-related proteins described in various plant species share the conserved domains D1, D2, BD, and D4. To define those BZI-1 domains involved in transcription factor function, BZI-1 deletion derivatives were expressed in transgenic plants. The domains D1 or BD are crucial for BZI-1-DeltaN function in planta. The basic BD domain is mediating DNA binding of BZI-1. Yeast two-hybrid and in vitro binding studies reveal the ankyrin-repeat protein ANK1, which specifically interacts with a part of the BZI-1 protein (amino acids 73-222) encoding the D1 domain. ANK1 does not bind DNA or act as a co-activator of BZI-1-mediated transcription. Moreover, green fluorescence protein localization studies propose that ANK1 is acting mainly inside the cytosol. Transcription analysis reveals that ANK1 is ubiquitously expressed, but after pathogen attack transcription is transiently down-regulated. Along these lines, ANK1 homologous proteins in Arabidopsis thaliana have been reported to function in pathogen defense. We therefore propose that the D1 domain serves as an interaction surface for ANK1, which appears to regulate BZI-1 function in auxin signaling as well as pathogen response.