Molecular Characterization of T-bet's Role in Immunity

T-bet 在免疫中的作用的分子表征

• 批准号: 7230470
• 负责人: Amy Susan Weinmann
• 金额: $ 28.75万
• 依托单位: UNIVERSITY OF WASHINGTON
• 依托单位国家: 美国
• 财政年份: 2004
• 资助国家: 美国
• 起止时间: 2004-06-01 至 2009-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7230470
• 关键词: Address; Allergic Reaction; Asthma; Autoimmune Diseases; Autoimmunity; B-Lymphocytes; Binding; Biological; Cell Lineage; Cells; Cellular Immunity; Characteristics; Chromatin; Crohn' s disease; Data; Defect; Dendritic Cells; Development; Disease; Disease model; Effector Cell; Elements; Environment; Event; Gene Expression; Gene Expression Alteration; Gene Targeting; Genes; Genomics; Goals; Hematopoietic; Hematopoietic System; Immune response; Immune system; Immunity; Individual; Lead; Lupus; Microarray Analysis; Modification; Molecular; Mus; Nuclear; Play; Population; Procedures; Process; RNA Polymerase II; Regulation; Repression; Role; Specificity; T-bet protein; Techniques; Th1 Cells; Thinking; Transactivation; Transcription Coactivator; Transcriptional Regulation; cell type; chromatin immunoprecipitation; chromatin remodeling; comparative; design; disease phenotype; insight; leukemia; macrophage; promoter; response; transcription factor

DESCRIPTION (provided by applicant): Lineage-restricted transcription factors play a critical role in the hematopoietic differentiation process and the deregulation of even a single factor can lead to disease states such as leukemia, autoimmunity, and allergic reactions. Part of how this occurs is that the selective loss of a factor can drastically alter the development of critical effector cell populations. Therefore, identifying the gene expression cascades influenced by these factors will allow us to address the molecular mechanisms that contribute to the disease phenotypes. The transcription factor T-bet appears to play a significant role in the development of CD4+ T helper 1 cells. Th1 cells secrete IFNgamma and are important in the development of cell-mediated immunity. A hyperactive Th1 response can contribute to autoimmune diseases such as Crohn's disease and type 1diabetes. In addition to Th1 cells, T-bet is also expressed in multiple lineages in the immune system and is thought to contribute to cell-specific functions in each effector cell population. In the absence of T-bet, cell-specific defects occur in natural killer, dendritic, and B cells. It is also worth noting that murine disease models for Crohn's disease, asthma, and lupus have all been established by altering T-bet levels. Therefore, one may hypothesize that T-bet plays an important role in the developing immune response. The main goal of this proposal is to address the molecular mechanisms behind T-bet's role in the individual hematopoietic effector cell populations. Aim 1 is designed to identify direct T-bet target genes in each cell population. Is T-bet targeted to loci in a cell-specific manner or does it interact with the same genes in all cellular settings? To address this question, target gene identification strategies will be employed that utilize modifications to the chromatin immunoprecipitation procedure. These techniques will only identify genes that are directly bound by T-bet within the context of a given nuclear environment. In Aim 2, the functional consequence of T-bet's association with select promoters will be examined to determine if this interaction is productive in the different cellular settings. The studies in Aim 1 and 2 will provide a means to address T-bet's cell-specifications. Aims 3 and 4 will address the role T-bet plays in the transcriptional regulation of a few select target genes. Does T-bet function as a transcriptional activator or repressor? Does T-bet influence chromatin events or aid in RNA polymerase II recruitment to the promoter? Detailed transcriptional regulation studies of a few select target genes will aid in answering these questions.

描述（由申请人提供）：谱系限制的转录因子在造血分化过程中起着至关重要的作用，即使是单个因素的放松管制也会导致疾病状态，例如白血病，自身免疫性和过敏反应。发生这种情况的一部分是，一个因子的选择性损失可以大大改变关键效应细胞群体的发展。因此，确定受这些因素影响的基因表达级联反应将使我们能够解决有助于疾病表型的分子机制。转录因子T-bet似乎在CD4+ T辅助1细胞的发展中起重要作用。 Th1细胞分泌Ifngamma，对于细胞介导的免疫的发展很重要。多动性TH1反应可以导致自身免疫性疾病，例如克罗恩病和1糖尿病。除Th1细胞外，T-bet还在免疫系统的多个谱系中表达，被认为有助于每个效应细胞群中的细胞特异性功能。在没有T-bet的情况下，自然杀手，树突状和B细胞中出现细胞特异性缺陷。还值得注意的是，克罗恩病，哮喘和狼疮的鼠类疾病模型都是通过改变T-BET水平建立的。因此，可以假设T-BET在发展免疫反应中起重要作用。该提案的主要目的是解决T-Bet在单个造血效应细胞群中的作用背后的分子机制。 AIM 1旨在识别每个细胞群中的直接T-BET靶基因。 T-BET是以细胞特异性的方式靶向基因座的，还是在所有细胞设置中与相同基因相互作用？为了解决这个问题，将采用目标基因识别策略，以利用染色质免疫沉淀程序进行修改。这些技术只会在给定的核环境的背景下识别直接被T-BET绑定的基因。在AIM 2中，将检查T-BET与选定启动子的关联的功能后果，以确定这种相互作用在不同的细胞环境中是否有效。 AIM 1和2中的研究将提供一种解决T-Bet细胞特异性的方法。 AIM 3和4将解决T-BET在少数选定靶基因的转录调控中的作用。 T-bet作为转录激活器或阻遏物的功能？ T-BET是否影响染色质事件或有助于RNA聚合酶II募集到启动子？一些精选靶基因的详细转录调节研究将有助于回答这些问题。