Role of RNA silencing in B cell development and function

RNA 沉默在 B 细胞发育和功能中的作用

• 批准号: 6902989
• 负责人: KLAUS RAJEWSKY
• 金额: $ 56.67万
• 依托单位: IMMUNE DISEASE INSTITUTE, INC.
• 依托单位国家: 美国
• 财政年份: 2005
• 资助国家: 美国
• 起止时间: 2005-03-01 至 2010-02-28
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6902989
• 关键词: B lymphocyte; RNA; antigen presentation; bioinformatics; cell differentiation; chromatin; dendritic cells; developmental immunology; double stranded RNA; gene induction /repression; immune response; immunogenetics; laboratory mouse; messenger RNA; microRNAs; small interfering RNA

DESCRIPTION (provided by applicant): RNA silencing is a novel, major biological mechanism controlling gene expression at the level of messenger RNA and chromatin, triggered by double-stranded RNA. Originally identified in lower organisms, recent results indicate that it also plays a crucial role in mammalian development and cell differentiation. Based on recent evidence that RNA silencing can affect B cell development, and strong indications that its dysregulation contributes to B cell lymphomagenesis, we hypothesize that RNA silencing plays specific roles at various stages of B cell development. The latter is a multi-stage process characterized by a sophisticated ordered interplay of chromosomal loci at which somatic gene rearrangements and mutation occur sequentially, accompanied by phases of cellular proliferation and quiescence and a continuous requirement for survival signals that rescue the cells from apoptosis. Together with the self-renewal capacity of certain mature B cell subsets, some of these features strikingly resemble processes that govern stem cell homeostasis and lineage commitment, known to be prime targets of control by RNA silencing. In the proposed experiments we will introduce targeted mutations into sequential stages of B cell development using Cre/loxP-mediated mutagenesis. Using this approach, we will first investigate the extent to which the RNA silencing machinery is required for proper B cell development and function, including the ability of the cells to execute adaptive immune responses and innate immune functions like antigen presentation to T cells. In the latter context, dendritic cells (DCs) will be included in the analysis. In these experiments we will use a conditional d/cerallele which we have generated, having demonstrated that Dicer is required for RNA silencing in mouse cells. Second, we will investigate whether the RNA silencing machinery is regulated during B cell development, and if so, try to understand the basis of such a control. Finally, we will identify and functionally characterize individual si/miRNAs that are selectively and stage-specifically expressed in B cells and DCs, using bioinformatic target gene predictions as a guide and targeted mutagenesis in mice. Overall, we expect new insights into the control of normal and malignant B cell development and the functional activity of B cells in adaptive and innate immune responses. Given the critical role of B cells in protective immunity, autoimmune diseases and lymphomagenesis, we anticipate this work will have significant medical relevance.

描述（由申请人提供）：RNA沉默是一种新颖的、主要的生物机制，在信使RNA和染色质水平上控制基因表达，由双链RNA触发。最初在低等生物中发现，最近的结果表明它在哺乳动物发育和细胞分化中也发挥着至关重要的作用。基于最近的证据表明 RNA 沉默可以影响 B 细胞发育，并且有充分证据表明 RNA 沉默会导致 B 细胞淋巴瘤发生，我们假设 RNA 沉默在 B 细胞发育的各个阶段发挥特定作用。后者是一个多阶段过程，其特征是染色体位点复杂有序的相互作用，其中体细胞基因重排和突变依次发生，伴随着细胞增殖和静止阶段以及对拯救细胞免于凋亡的生存信号的持续需求。连同某些成熟 B 细胞亚群的自我更新能力，其中一些特征与控制干细胞稳态和谱系定型的过程惊人地相似，这些过程被认为是 RNA 沉默控制的主要目标。在拟议的实验中，我们将使用 Cre/loxP 介导的诱变将靶向突变引入 B 细胞发育的连续阶段。使用这种方法，我们将首先研究 B 细胞正常发育和功能所需的 RNA 沉默机制的程度，包括细胞执行适应性免疫反应和先天免疫功能（如向 T 细胞呈递抗原）的能力。在后一种情况下，树突状细胞 (DC) 将包含在分析中。在这些实验中，我们将使用我们生成的条件 d/cerallele，并证明 Dicer 是小鼠细胞中 RNA 沉默所必需的。其次，我们将研究 RNA 沉默机制在 B 细胞发育过程中是否受到调节，如果是，则尝试了解这种控制的基础。最后，我们将使用生物信息学靶基因预测作为指导并在小鼠中进行定向诱变，鉴定并功能表征在 B 细胞和 DC 中选择性和阶段特异性表达的个体 si/miRNA。总体而言，我们期望对正常和恶性 B 细胞发育的控制以及 B 细胞在适应性和先天免疫反应中的功能活性有新的见解。鉴于 B 细胞在保护性免疫、自身免疫性疾病和淋巴瘤发生中的关键作用，我们预计这项工作将具有重要的医学意义。