Molecular mechanisms of interplay between ethylene signaling and chromatin regulation in Arabidopsis

 描述（申请人提供）：细胞核的功能是维持基因的完整性，并通过调节基因表达来控制细胞的活动。核酶、染色质及其修饰有助于细胞和生物体在动态环境中反应和生存的能力。核过程功能障碍直接导致癌症进展和遗传疾病。我们正在利用拟南芥研究乙烯信号的早期核事件，这不仅在植物生长和发育中很重要，而且在对干旱，洪水和感染等胁迫的各种反应中也很重要。我们的长期目标是开发一个经过验证的机制模型，准确地描述了染色质调节器如何接收信号，以及如何在乙烯信号传导中首先建立调节。在乙烯信号通路中，EIN 2是必需的关键调节子，并且它是唯一的无效突变体使乙烯完全不敏感的基因。我们最近的研究表明，EIN 2介导起源于内质网膜的乙烯信号传导到细胞核，并且EIN 2 C-末端被切割并易位到细胞核以启动乙烯反应。然而，EIN 2核转位的分子机制、EIN 2 C末端在细胞核中的功能以及EIN 2 C末端如何与EIN 3进行通讯尚不清楚。通过广泛的酵母双杂交筛选和免疫沉淀，然后质谱分析，我们确定了一个强大的EIN 2的C-末端相互作用。这种蛋白质定位于细胞核， 并且引人注目的是，它与组蛋白相关并且参与组蛋白修饰的调节。我们的初步数据强烈表明，EIN 2的C-末端参与组蛋白修饰，提供了信号和染色质调控之间的联系。本研究的具体目标是：（1）确定EIN 2 C端的功能，并鉴定和表征参与乙烯信号早期核反应的其他组分的功能;（2）揭示染色质调控子如何接受乙烯信号，从而启动特异性转录调控的机制。研究中的分子机制涉及染色质调控和转录重编程，这在植物和动物中是普遍共享的;（3）阐明EIN 2 C-末端响应乙烯易位到细胞核的分子机制。

 DESCRIPTION (provided by applicant): The function of the nucleus is to maintain the integrity of genes and to control the activities of the cell by regulating gene expression. Nuclear enzymes, chromatin and its modifications contribute to the abilities of cells and organisms to respond and survive in dynamic environments. Dysfunctions nuclear processes contribute directly to cancer progression and genetic disorders. We are using Arabidopsis to study early nuclear events in ethylene signaling, which is important not only in plant growth and development, but also in various responses to stresses such as drought, flooding, and infection. Our long-term goal is to develop a validated mechanistic model that accurately describes how chromatin regulators receive signals and how the regulation is established in the first place in ethylene signaling. In the ethylene signaling pathway, EIN2 is the essential key regulator, and it is the only gene whose null mutant renders completely ethylene insensitive. Our recent studies have revealed that EIN2 mediates transmission of ethylene signaling that originates at the endoplasmic reticulum membrane to the nucleus and that the EIN2 C-terminus is cleaved and translocated to the nucleus to initiate the ethylene response. However, the molecular mechanism that nuclear translocation of EIN2, the function of EIN2 C-terminal end in the nucleus and how EIN2 C-terminal end communicate with EIN3 are not understood. Through extensive yeast two-hybrid screening and immunoprecipitation followed by mass spectrometry assay, we identified a strong EIN2 C-terminus interactor. This protein is localized to the nucleus, and strikingly, it is associated with histones and involved in the regulation of histone modifications. Our preliminary data strongly indicate that the EIN2 C-terminus participates in histone modification, providing a link between signaling and chromatin regulation. This proposal has the following specific aims: (1) Determine the function of EIN2 C-terminus and identify and characterize functions of other components involved in the early nuclear response to ethylene signaling; (2) Uncover the mechanism that how chromatin regulators receive ethylene signaling to regulate the initiation of the specific transcriptional regulation. The molecular mechanisms under investigation involve chromatin regulation and transcriptional reprogramming, which are shared in general in both plants and animals; (3) Elucidate the molecular mechanisms by which EIN2 C-terminal is translocated to the nucleus in response to ethylene.