Explore FOXP3's role in the 3D organization of the genome

描述（由申请人提供）：探索FOXP3在基因组3D组织中的作用。FOXP3是一种在调节性T细胞（Tcells）中表达的转录因子，对免疫系统的平衡功能至关重要。甲状腺素抑制自身反应性T细胞的活性; FOXP3的功能丧失突变与自身免疫性疾病很相似。F0XP3在Treg的发育和功能中的关键作用以及利用基于Treg的疗法（例如移植排斥）的潜力已经吸引了对F0XP3的基本功能机制的大量关注。FOXP3结合位点的全基因组分析（ChIP-on-chip和ChIP-seq）结合表达谱分析揭示了数千个潜在的FOXP3激活或抑制基因。尽管这些基因中的一些随后被证明对Treg是重要的，但仍然缺乏对FOXP3介导的基因表达和Treg功能之间的机制理解。这项研究旨在通过探索FOXP3在基因组3D组织中的作用来解决这个问题。先前对FOXP3的结构/功能研究揭示了一种意想不到的结构域交换机制，该机制是TcP的抑制功能所必需的。初步证据表明，结构域交换的FOXP3二聚体可能已经进化为桥接DNA，从而介导长距离染色质相互作用。这种转录调控模式早已被认识到，并在近年来获得了相当大的关注，但远距离染色质相互作用的分子基础还没有得到表征。FOXP3提供了一个理想的系统来解决这个问题，这反过来又可以深入了解FOXP3在Tumor中的机制作用。拟议的研究有以下三个具体目标。目的1：通过测定FOXP3与DNA及其高级寡聚体复合物的结构，来表征FOXP3对DNA桥连的结构基础。目的2是测试FOXP3是否可以在生物化学水平上直接桥接DNA，以及FOXP3是否可以调节细胞内的长距离基因-基因相互作用。目的3是利用新开发的染色体构象捕获技术，探索FOXP3对T细胞基因组整体结构的影响。拟议的研究旨在推进FOXP3如何通过基因组3D结构的全局重组来调节特定基因表达的基本知识。这些研究将为研究FOXP3在TcB中的抑制作用机制提供新的视角，并有助于开发基于Treg的自身免疫性/炎症性疾病治疗和癌症免疫治疗。

DESCRIPTION (provided by applicant): Explore FOXP3's role in the 3D organization of the genome. FOXP3 is a transcription factor expressed in regulatory T cells (Tregs) that are essential for the balanced function of the immune system. Tregs suppresses the activity of autoreactive T cells; loss-of-function mutations in FOXP3 are casually liked to autoimmune diseases. The critical role of FOXP3 in the development and function of Tregs and the potential to harness Treg-based therapies (e.g. transplantation rejection) have attracted much attention to the basic functional mechanism of FOXP3. Genome-wide analyses of FOXP3 binding sites (ChIP-on-chip and ChIP-seq) coupled with expression profiling reveal thousands of potential FOXP3- activated or repressed genes. Although some of these genes have subsequently been shown to be important to Treg, a mechanistic understanding between FOXP3-mediated gene expression and Treg function is still lacking. The proposed research intends to adress this question by exploring FOXP3's role in the 3D organization of the genome. Previous structure/function studies of FOXP3 reveal an unexpected domain- swapping mechanism that is required for the suppression function of Tregs. Preliminary evidence suggests that the domain-swapped FOXP3 dimer may have evolved to bridge DNA, thereby mediating long-range chromatin interactions. This mode of transcription regulation has long been recognized and has gained considerable attention in recent years, but the molecular basis underlying the long-distance chromatin interactions has not been characterized. FOXP3 provides an ideal system to address this question, which in turn can yield insights into the mechanistic roles of FOXP3 in Tregs. The proposed research has the following three specific aims. Aim 1 is to characterize the structural basis of DNA bridging by FOXP3 by determining the structures of FOXP3 bound to DNA and its higher-order oligomer complex. Aim 2 is to test if FOXP3 can directly bridge DNA at the biochemical level and if FOXP3 can regulates long distance gene-gene interactions inside cells. Aim 3 is to explore the effects of FOXP3 on the global architecture of the T cell genome using a newly developed chromosome conformation capture technology. The proposed studies seek to advance basic knowledge on how FOXP3 regulates specific gene expression via global reorganization of the 3D architecture of the genome. These studies will provide a new angle to study the mechanism by which FOXP3 confers the suppression function in Tregs and aid the development of Treg-based therapies in autoimmune/inflammatory diseases and immunotherapy of cancer.