Organization and Expression of V Genes

V基因的组织和表达

• 批准号: 6773701
• 负责人: PETER H BRODEUR
• 金额: $ 31.7万
• 依托单位: TUFTS UNIVERSITY BOSTON
• 依托单位国家: 美国
• 财政年份: 1985
• 资助国家: 美国
• 起止时间: 1985-07-01 至 2008-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6773701
• 关键词: B lymphocyte; acetylation; alleles; biological signal transduction; bone marrow; cell line; chromatin; chromatin immunoprecipitation; cytokine receptors; gel mobility shift assay; gene expression; gene targeting; genetic regulatory element; genetically modified animals; histones; immunogenetics; immunoglobulin genes; interleukin 7; laboratory mouse; polymerase chain reaction; transfection

DESCRIPTION (provided by applicant): Antigen specific receptors of B and T lineage cells require the somatic assembly of V, D, and J gene segments during lymphocyte development. Immunoglobulin and T cell receptor loci are targeted by a common V(D)J recombinase in a cell type- and developmental stage-specific manner. The fundamental control of this process occurs at the level of alterations in chromatin structure that confer locus "accessibility" to the RAG1/2 complex. The immunoglobulin heavy chain locus (Igh) is the first to rearrange during B cell differentiation and accessibility at different stages is limited to discrete domains. The cis-acting elements and signaling pathways that regulate accessibility throughout the lgh locus are yet to be fully elucidated. Since V(D)J recombination is required for normal lymphocyte development, defects in the process result in both subtle and catastrophic immune deficiencies. Thus, understanding the underlying mechanisms has obvious implications to health and disease. Our long term goals are focused on the control of Igh locus accessibility within the nearly 3 megabase region containing approximately 200 Vh gene segments. In this application, we propose to extend our studies of a candidate control region in the 5' boundary of the lgh locus that exhibits early B cell specific chromatin remodeling. This novel region interacts, both in vitro and in vivo, with factors that have been implicated in Igh accessibility and rearrangement. We propose to examine sorted early B cell subsets from bone marrow to determine the precise stage of B cell development at which this element is active. Gel shift and chromatin immunoprecipitation approaches will be used to define the factors that are recruited to the multiple sites mapped within this region. The function of this putative regulatory element will be tested by both genomic deletion and studies of BAC transgenes containing putative control regions and Vh segments of the 5' region of the locus. We will use a novel cell line model as well as primary bone marrow cells to determine the mechanism through which IL-7 receptor signaling selectively mediates D-distal (5') Vh gene accessibility.

描述（由申请人提供）：B 和 T 谱系细胞的抗原特异性受体需要在淋巴细胞发育过程中进行 V、D 和 J 基因片段的体细胞组装。常见的 V(D)J 重组酶以细胞类型和发育阶段特异性的方式靶向免疫球蛋白和 T 细胞受体位点。这一过程的基本控制发生在染色质结构的改变水平上，这些改变赋予了 RAG1/2 复合体基因座的“可接近性”。免疫球蛋白重链位点 (Igh) 是 B 细胞分化过程中第一个重排的位点，不同阶段的可及性仅限于离散的结构域。调节整个 lgh 基因座可及性的顺式作用元件和信号通路尚未完全阐明。由于正常淋巴细胞发育需要 V(D)J 重组，因此该过程中的缺陷会导致微妙和灾难性的免疫缺陷。因此，了解潜在的机制对健康和疾病具有明显的影响。我们的长期目标集中于控制包含约 200 个 Vh 基因片段的近 3 兆碱基区域内的 Igh 基因座可及性。在此应用中，我们建议扩展对 lgh 基因座 5' 边界中的候选控制区域的研究，该区域表现出早期 B 细胞特异性染色质重塑。这个新区域在体外和体内都与 Igh 可及性和重排相关的因素相互作用。我们建议检查骨髓中分选的早期 B 细胞亚群，以确定该元件处于活跃状态的 B 细胞发育的精确阶段。凝胶位移和染色质免疫沉淀方法将用于定义被招募到该区域内多个位点的因子。该假定调节元件的功能将通过基因组删除和含有假定控制区和基因座 5' 区 Vh 片段的 BAC 转基因研究来测试。我们将使用新型细胞系模型以及原代骨髓细胞来确定 IL-7 受体信号选择性介导 D-远端 (5') Vh 基因可及性的机制。