Feedback Regulation of DYT1 by Interactions with Downstream bHLH Factors Promotes DYT1 Nuclear Localization and Anther Development
Feedback Regulation of DYT1 by Interactions with Downstream bHLH Factors Promotes DYT1 Nuclear Localization and Anther Development
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通过与下游 bHLH 因子相互作用对 DYT1 进行反馈调节，促进 DYT1 核定位和花药发育
DOI：
10.1105/tpc.15.00986
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发表时间：
2016-05-01
期刊：
影响因子：
11.6
通讯作者：
Chang, Fang
中科院分区：
文献类型：
--
作者：
Cui, Jie;You, Chenjiang;Chang, Fang
转录调控是控制动植物发育和细胞功能的重要机制之一。拟南芥bHLH转录因子（TF）DYT 1（DYT 1）是正常雄性育性和花药发育所需的，并激活bHLH 010/bHLH 089/bHLH 091基因的表达。在这里，我们发现，DYT 1是本地化的细胞质和细胞核在花药阶段5，但具体到细胞核在花药阶段6及以后。bHLH 010/bHLH 089/bHLH 091蛋白具有强的核定位信号，与DYT 1相互作用，并促进DYT 1的核定位。我们进一步发现DYT 1保守的C-末端BIF结构域是其二聚化、核定位、转录激活活性和在花药发育中的功能所必需的。有趣的是，当DYT 1的BIF结构域被bHLH 010的BIF结构域取代时，DYT 1 N-bHLH 010 BIF嵌合蛋白在花药阶段5显示出核优先定位，但不能完全拯救dyt 1 -3表型，这表明DYT 1的正常时空亚细胞定位对DYT 1功能很重要和/或来自不同bHLH成员的BIF结构域可能在功能上不同。我们的研究结果支持了一个重要的正反馈调节机制，即下游TF通过BIF结构域增强其核定位来增加上游TF的功能。
Transcriptional regulation is one of the most important mechanisms controlling development and cellular functions in plants and animals. The Arabidopsis thaliana bHLH transcription factor (TF) DYSFUNCTIONL TAPETUM1 (DYT1) is required for normal male fertility and anther development and activates the expression of the bHLH010/bHLH089/bHLH091 genes. Here, we showed that DYT1 is localized to both the cytoplasm and nucleus at anther stage 5 but specifically to the nucleus at anther stage 6 and onward. The bHLH010/bHLH089/bHLH091 proteins have strong nuclear localization signals, interact with DYT1, and facilitate the nuclear localization of DYT1. We further found that the conserved C-terminal BIF domain of DYT1 is required for its dimerization, nuclear localization, transcriptional activation activity, and function in anther development. Interestingly, when the BIF domain of DYT1 was replaced with that of bHLH010, the DYT1N-bHLH010BIF chimeric protein shows nuclear-preferential localization at anther stage 5 but could not fully rescue the dyt1-3 phenotype, suggesting that the normal spatio-temporal subcellular localization of DYT1 is important for DYT1 function and/or that the BIF domains from different bHLH members might be functionally distinct. Our results support an important positive feedback regulatory mechanism whereby downstream TFs increase the function of an upstream TF by enhancing its nucleus localization through the BIF domain.