Regulation of V(D)J Recombination by Arginine Methylation

精氨酸甲基化对 V(D)J 重组的调节

• 批准号: 9087092
• 负责人: James R. Hagman
• 金额: $ 19.81万
• 依托单位: NATIONAL JEWISH HEALTH
• 依托单位国家: 美国
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-06-15 至 2017-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9087092
• 关键词: Abelson murine leukemia virus; Address; Antibodies; Antigen Receptors; Arginine; Autoimmunity; B-Cell Development; B-Lymphocytes; Binding; Biochemical; Biological Assay; Categories; Cell Line; Cell membrane; Cells; Citrulline; Cleaved cell; Complex; Controlled Study; DNA; DNA Methylation; Data; Development; Dioxygenases; Environment; Enzymes; Epigenetic Process; Event; Excision; Exploratory/Developmental Grant; Family; Future; Gene Expression; Gene Expression Regulation; Gene Rearrangement; Generations; Genes; Genetic Recombination; Genetic Transcription; Health; Histone H2A; Histone H3; Histones; Imatinib; Immunity; Immunoglobulin Genes; In Vitro; Ligation; Literature; Lymphocyte; Lysine; Malignant Neoplasms; Messenger RNA; Methods; Methylation; Modification; Monitor; Pathway interactions; Peptide Signal Sequences; Post-Translational Protein Processing; Process; Protein Family; Protein-Arginine N-Methyltransferase; Proteins; RAG1 gene; Rag1 Mouse; Receptors, Antigen, B-Cell; Recombinants; Regulation; Risk; Role; Series; Specific qualifier value; Specificity; Staging; T-Cell Receptor; T-Lymphocyte; Thymoma; Transcript; Tyrosine Kinase Inhibitor; V(D)J Recombination; VDJ Recombinases; abl Oncogene; adaptive immunity; chromatin immunoprecipitation; demethylation; experience; immunoglobulin light chain locus; member; methyl group; non-histone protein; novel; pathogen; progenitor; protein structure function; research study; small hairpin RNA; thymocyte; transcription factor

DESCRIPTION (provided by applicant): V(D)J recombination is the hallmark of adaptive immunity. In T and B cells, a series of highly regulated somatic gene rearrangement events produce functional genes from gene segments. This process results in the expression of functional antigen receptors. Immunoglobulin (Ig) genes encode B cell receptors, while T cell receptors are encoded by Tcr loci. The central mechanisms necessary for the assembly of these genes are cleavage and ligation of variable (V), diversity (D, at a subset of antigen receptor loci), and Joining (J) segments by V(D)J recombination. V(D)J recombinase complexes comprise multiple proteins including Recombination activating genes 1 and 2 (Rag1 and Rag2), which recognize and cleave recombination signal sequences (RSS) when RSS are in an 'accessible' state. Here, we will determine the roles of Protein Arginine Methyltransferase 5 (PRMT5), methylated arginine, and its removal by epigenetic 'erasers' in this process. Accessibility of RSS for recombination is largely controlled by epigenetic mechanisms including DNA methylation and post-translational modifications of histones. The importance of each of these mechanisms has been documented in V(D)J recombination. However, far less is understood concerning the importance of arginine methylation and the identities of enzymes that add or remove methyl groups from arginine during lymphocyte development. We hypothesize that V(D)J recombination of T cell receptor (Tcra) loci is regulated by PRMT5, which dimethylates arginine symmetrically at multiple residues of histones H3 and H4, as well as some non-histone proteins. Provocatively, Prmt5 transcripts are expressed in developing thymocytes (and B cells), but not at stages that express the Rag1 gene and feature ongoing V(D)J recombination. These observations suggest that arginine methylation by PRMT5 inhibits V(D)J recombination. Indeed, depletion of Prmt5 mRNA in a pre-T cell line greatly increases mature TCR� expression on the plasma membrane. We predict that this mechanism regulates antigen receptor assembly in both T and B cells. Therefore, we will address functions of arginine methylation and PRMT5 in T and B cell lines that undergo efficient V(D)J recombination in vitro. Our evidence suggests that the loss of arginine methylation is an active process involving one or more epigenetic erasers, which are likely members of the Jumonji family of protein dioxigenases. We will use biochemical methods to identify candidate arginine demethylases in lymphocyte progenitors. Together, our experiments will address novel epigenetic mechanisms that control antigen receptor assembly during lymphocyte development, but are also important for gene regulation in a wide variety of contexts including cancer.

描述（由申请人提供）：V(D)J重组是适应性免疫的标志，一系列高度调控的体细胞基因重排事件从基因片段中产生功能性基因，该过程导致功能性基因的表达。免疫球蛋白 (Ig) 基因编码 B 细胞受体，而 T 细胞受体则由 Tcr 基因座编码。这些基因组装所需的核心机制是裂解和连接。可变(V)、多样性(D，在抗原受体位点的子集)和通过V(D)J重组连接(J)片段包含多个包括蛋白质重组激活基因1和2( Rag1 和 Rag2)，当 RSS 处于“可访问”状态时，它们识别并切割重组信号序列 (RSS) 在这里，我们将确定蛋白质精氨酸甲基转移酶的作用。 5 (PRMT5)，甲基化精氨酸，以及在此过程中通过表观遗传“擦除器”去除 RSS 的重组能力很大程度上受表观遗传机制的控制，包括 DNA 甲基化和组蛋白翻译后修饰。这些机制的重要性各不相同。然而，对于精氨酸甲基化的重要性以及添加或去除甲基的酶的特性，人们了解甚少。我们研究了 T 细胞受体 (Tcra) 位点的 V(D)J 重组受 PRMT5 的调节，PRMT5 在组蛋白 H3 和 H4 以及一些非组蛋白蛋白的多个残基上对称地二甲基化精氨酸。 , Prmt5 转录物在发育中的胸腺细胞（和 B 细胞）中表达，但在表达 Rag1 基因并具有持续 V(D)J 特征的阶段不表达这些观察结果表明，PRMT5 的精氨酸甲基化会抑制 V(D)J 重组。事实上，前 T 细胞系中 Prmt5 mRNA 的耗尽会增加质膜上成熟的 TCR 表达。因此，我们将研究在体外进行有效 V(D)J 重组的 T 和 B 细胞系中精氨酸甲基化和 PRMT5 的功能。精氨酸甲基化的丧失是一个主动过程，涉及一个或多个表观遗传擦除器，这些擦除器可能是 Jumonji 蛋白双加氧酶家族的成员，我们将使用生化方法来鉴定淋巴细胞祖细胞中的候选精氨酸去甲基化酶。表观遗传机制在淋巴细胞发育过程中控制抗原受体组装，但对于包括癌症在内的多种情况下的基因调控也很重要。

项目成果

EBF1 and PAX5 control pro-B cell expansion via opposing regulation of the Myc gene.

• DOI: 10.1182/blood.2020009564
• 发表时间: 2021-02
• 期刊: Blood
• 影响因子: 20.3
• 作者: R. Somasundaram;Christina T. Jensen;Johanna Tingvall-Gustafsson;Josefine Åhsberg;K. Okuyama;M. Prasad;J. Hagman;Xun Wang;S. Soneji;Tobias Strid;Jonas Ungerbäck;M. Sigvardsson