Molecular Characterization of T-bet's Role in Immunity

T-bet 在免疫中的作用的分子表征

基本信息

批准号：
6892078
负责人：
Amy Susan Weinmann
金额：
$ 30.32万
依托单位：
UNIVERSITY OF WASHINGTON
依托单位国家：
美国
项目类别：
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

项目摘要

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（申请人提供）：谱系限制性转录因子在造血分化过程中发挥着关键作用，即使是单个因子的失调也可能导致白血病、自身免疫和过敏反应等疾病状态。发生这种情况的部分原因是因子的选择性丢失可以极大地改变关键效应细胞群的发育。因此，识别受这些因素影响的基因表达级联将使我们能够解决导致疾病表型的分子机制。转录因子 T-bet 似乎在 CD4+ T 辅助 1 细胞的发育中发挥着重要作用。 Th1 细胞分泌 IFNgamma，对于细胞介导的免疫的发展非常重要。过度活跃的 Th1 反应可能导致自身免疫性疾病，例如克罗恩病和 1 型糖尿病。除了 Th1 细胞外，T-bet 还在免疫系统的多个谱系中表达，并且被认为有助于每个效应细胞群的细胞特异性功能。在缺乏 T-bet 的情况下，自然杀伤细胞、树突状细胞和 B 细胞中会出现细胞特异性缺陷。还值得注意的是，克罗恩病、哮喘和狼疮的小鼠疾病模型都是通过改变 T-bet 水平建立的。因此，人们可以假设 T-bet 在免疫反应的发展中发挥着重要作用。该提案的主要目标是解决 T-bet 在个体造血效应细胞群中作用背后的分子机制。目标 1 旨在识别每个细胞群中的直接 T-bet 目标基因。 T-bet 是否以细胞特异性方式针对基因座，或者它是否与所有细胞环境中的相同基因相互作用？为了解决这个问题，将采用对染色质免疫沉淀程序进行修改的靶基因识别策略。这些技术只能识别在给定核环境中直接受 T-bet 结合的基因。在目标 2 中，将检查 T-bet 与选定启动子关联的功能结果，以确定这种相互作用在不同的细胞环境中是否有效。目标 1 和 2 中的研究将提供一种解决 T-bet 细胞规格的方法。目标 3 和 4 将解决 T-bet 在一些选定目标基因的转录调控中所发挥的作用。 T-bet 是转录激活子还是抑制子？ T-bet 是否会影响染色质事件或有助于 RNA 聚合酶 II 募集至启动子？对一些选定的靶基因进行详细的转录调控研究将有助于回答这些问题。