An Arabidopsis transcription factor, AtbZIP60, regulates the endoplasmic reticulum stress response in a manner unique to plants
An Arabidopsis transcription factor, AtbZIP60, regulates the endoplasmic reticulum stress response in a manner unique to plants
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DOI：
10.1073/pnas.0408941102
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发表时间：
2005-04-05
影响因子：
11.1
通讯作者：
Koizumi, N
中科院分区：
文献类型：
--
作者：
Iwata, Y;Koizumi, N
对拟南芥基因组中编码假定的碱性亮氨酸拉链（bZIP）转录因子的75个基因的转录本进行分析，鉴定出AtbZIP 60，其被衣霉素诱导。AtbZIP 60编码295个氨基酸的蛋白质，在其C端附近的bZIP结构域之后具有推定的跨膜结构域。不具有跨膜结构域的AtbZIP 60的截短形式（AtbZIP 60 Δ C）与定位于细胞核的GFP融合，表明天然蛋白通过从膜释放而易位至细胞核。AtbZIP 60也被DTT和氮杂环丁烷-2-羧酸诱导，其诱导内质网（ER）应激反应（也称为未折叠蛋白反应）。在使用培养细胞的原生质体的双荧光素酶测定中，AtbZIP 60 Δ C的表达清楚地激活了三种BiP和两种钙连接蛋白启动子中的任何一种。这种诱导被认为是通过顺式元件、植物特异性未折叠蛋白反应元件和内质网应激反应元件进行的。有趣的是，AtbZIP 60 Delta C似乎也通过AtbZIP 60启动子中的ER应激反应元件样序列诱导AtbZIP 60的表达。AtbZIP 60的这些特性暗示了植物特有的内质网应激反应的信号转导途径。
Analysis of transcripts of 75 genes encoding putative basic leucine zipper (bZIP) transcription factors in the Arabidopsis genome identified AtbZIP60, which was induced by tunicamycin. AtbZIP60 encodes a predicted protein of 295 aa with a putative transmembrane domain near its C terminus after a bZIP domain. A truncated form of AtbZIP60 without a transmembrane domain (AtbZIP60 Delta C) fused with GFP localized to the nucleus, suggesting translocation of native protein to the nucleus by release from the membrane. AtbZIP60 was also induced by DTT and azetidine-2-carboxylate, which induce the endoplasmic reticulum (ER) stress response (also called the unfolded protein response). Expression of AtbZIP60 Delta C clearly activated any of three BiP and two calnexin promoters in a dual luciferase assay using protoplasts of cultured cells. The induction was considered to be through cis-elements plant-specific unfolded protein response element and ER stress-response element. Interestingly, AtbZIP60 Delta C also appeared to induce the expression of AtbZIP60 through an ER stress-response element-like sequence in the promoter of AtbZIP60. These characteristics of AtbZIP60 imply a signal transduction pathway of the ER stress response unique to plants.