Emerin functions in transcriptional regulation

描述(由申请人提供)： 真核生物中核膜的存在在功能上将转录和翻译过程分开。使这些过程分离的能力有助于建立更大的转录和翻译调控。核膜由与内质网相邻的外核膜和内核膜组成。INM含有许多与层蛋白和染色质相关蛋白结合的完整膜蛋白。其中一种名为Emerin的蛋白质直接与核膜和一种名为Barrier-to-AutoIntegration(BAF)的染色质相关蛋白质结合。有趣的是，Emerin的突变或缺失会导致隐性的Emery-Dreifuss肌营养不良症(EDMD)。虽然Emerin在大多数被测试的细胞类型中都有表达，但EDMD专门针对肌肉和脂肪组织，这表明Emerin在组织特异性功能中发挥了作用。最近研究表明，另一种INM蛋白Lap213与转录抑制因子无生殖细胞(GCL)相互作用。由于Lab2beta和Emerin有一个重要的同源性区域，我测试了Emerin是否可以与转录抑制物相互作用。GCL和EBP1(另一种转录调控因子)都与Emerin结合。我认为Emerin可能在核膜上招募转录调节因子，并在此形成功能抑制物或激活物复合体。为了测试此模型，我将精细映射此交互所需的Emerin、GCL和EBP1内的功能域。通过突变分析，我将确定与GCL和EBP1相互作用的Emerin结构域(S)(S)。还将在GCL和EBP中进行突变，以定位每种蛋白质中的“Emerin结合域”。一旦确定，(Se)Emerin结合结构域(S)将被用于识别其他Emerin结合蛋白。这些相互作用的初步特征将作为在我自己的实验室中研究核膜在转录调控中的作用的基础。

DESCRIPTION (provided by applicant): The presence of the nuclear envelope in eukaryotes functionally separates the processes of transcription and translation. The ability to have these processes disjoined serves to establish greater transcriptional and translational regulation. The nuclear envelope consists of an outer nuclear membrane, which is contiguous with the endoplasmic reticulum, and an inner nuclear membrane (INM). The INM contains numerous integral membrane proteins that bind to both lamins and chromatin-associated proteins. One of these proteins, emerin, directly binds the nuclear lamina and a chromatin associated protein named Barrier-to-Autointegration (BAF). Interestingly, mutation or deletion of emerin causes the recessive form of Emery-Dreifuss muscular dystrophy (EDMD). Although emerin is expressed in most cell types tested, EDMD specifically targets muscle and adipose tissue, suggesting a role for emerin in tissue-specific functions. Recently it has been demonstrated that another INM protein, Lap213, interacts with a transcriptional repressor, germ-cell-less (GCL). Since Lab2beta and emerin share a significant region of homology, I tested whether emerin could interact with transcriptional repressors. Both GCL and EBP1, another transcriptional regulator, bind emerin. I propose that emerin may recruit transcriptional regulators to the nuclear envelope and form functional repressor or activator complexes here. To test this model, I will fine-map the functional domains within emerin, GCL, and EBP1 necessary for this interaction. Using mutational analysis, I will identify the domain(s) in emerin that interact(s) with GCL and EBP1. Mutations will also be made in GCL and EBP in order to map the 'emerin binding domain' in each of these proteins. Once identified, the(se) emerin binding domain(s) will be used to identify other emerin binding proteins. The initial characterization of these interactions will serve as the foundation for studying the role of the nuclear envelope in transcriptional regulation in my own laboratory.