The plant-specific transcription factor gene NAC103 is induced by bZIP60 through a new cis-regulatory element to modulate the unfolded protein response in Arabidopsis
The plant-specific transcription factor gene NAC103 is induced by bZIP60 through a new cis-regulatory element to modulate the unfolded protein response in Arabidopsis
复制标题
植物特异性转录因子基因 NAC103 由 bZIP60 通过新的顺式调控元件诱导，以调节拟南芥中的未折叠蛋白反应
DOI：
10.1111/tpj.12287
复制
发表时间：
2013-10-01
期刊：
影响因子：
7.2
通讯作者：
Liu, Jian-Xiang
中科院分区：
文献类型：
--
作者：
Sun, Ling;Yang, Zheng-Ting;Liu, Jian-Xiang
未折叠蛋白反应（UPR）在植物发育、植物与病原菌互作以及植物对逆境胁迫的适应中起着重要作用。以前bZIP 28和bZIP 60已被确定为减轻拟南芥内质网（ER）胁迫的重要UPR调节剂。在这里，我们报告了NAC 103在一个新的转录调控级联中的生物学功能，将bZIP 60连接到拟南芥中的UPR下游基因。NAC 103的表达由ER应激诱导，并且在bZIP 60无效突变体中被完全消除。在NAC 103启动子上鉴定了一个新的ER胁迫响应顺式元件UPRE-III（TCATCG），并在酵母细胞和拟南芥原生质体中证实了bZIP 60对UPRE-III的反式激活。在电泳迁移率变动分析中也证明了bZIP 60与含UPRE-III的DNA的直接结合。NAC 103在酵母双杂交和双分子荧光互补测定中形成同源二聚体。它具有转录激活活性，定位于细胞核。过量表达NAC 103对植物生长具有多效性，在正常生长条件下诱导拟南芥中几个UPR下游基因的表达。NAC 103对UPR基因启动子的激活也在效应子/报告子原生质体测定中得到证实。因此，我们的研究证明了一个转录调控级联，其中NAC 103中继ER应力信号从bZIP 60到UPR下游基因，通过一个新发现的ER应力顺式元件（UPRE-III）及其编码蛋白NAC 103的转录激活活性。
The unfolded protein response (UPR) plays important roles in plant development and plant-pathogen interactions, as well as in plant adaptation to adverse environmental stresses. Previously bZIP28 and bZIP60 have been identified as important UPR regulators for mitigating the endoplasmic reticulum (ER) stress in Arabidopsis thaliana. Here we report the biological function of NAC103 in a novel transcriptional regulatory cascade, connecting bZIP60 to the UPR downstream genes in Arabidopsis. Expression of NAC103 was induced by ER stress, and was completely abolished in the bZIP60 null mutant. A new ER stress-responsive cis-element UPRE-III (TCATCG) on the NAC103 promoter was identified, and trans-activation of UPRE-III by bZIP60 was confirmed in both yeast cells and Arabidopsis protoplasts. The direct binding of bZIP60 to UPRE-III-containing DNA was also demonstrated in an electrophoretic mobility shift assay. NAC103 formed homodimers in yeast two-hybrid and bimolecular fluorescence complementation assays. It had transcriptional activation activity and was localized in the nucleus. Over-expression of NAC103 had pleiotropic effects on plant growth, and induced expression of several UPR downstream genes in Arabidopsis under normal growth conditions. The activation of UPR gene promoters by NAC103 was also confirmed in effector/reporter protoplast assays. Thus, our study demonstrates a transcriptional regulatory cascade in which NAC103 relays ER stress signals from bZIP60 to UPR downstream genes through a newly identified ER stress cis-element (UPRE-III) and transcriptional activation activity of its encoded protein NAC103.