ELUCIDATION OF IMMUNOGLOBULIN CLASS SWITCH RECOMBINATION AND SOMATIC HYPERMUTATIO

免疫球蛋白类别转换重组和体细胞超突变的阐明

基本信息

批准号：
8500117
负责人：
Jayanta Chaudhuri
金额：
$ 43.67万
依托单位：
SLOAN-KETTERING INST CAN RESEARCH
依托单位国家：
美国
项目类别：
财政年份：
2009
资助国家：
美国
起止时间：
2009-07-01 至 2014-11-14
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/8500117
关键词：
Address Affect Affinity Alanine Antibodies Antibody Formation Antigens B-Cell Lymphomas B-Cell Neoplasm B-Lymphocytes Bacterial Infections Binding Binding Proteins Biochemical Biological Assay Catalytic Domain Cells Chromatin Complex Cyclic AMP Cyclic AMP-Dependent Protein Kinases Cytidine DNA DNA Double Strand Break DNA-Binding Proteins Deamination Double Strand Break Repair Elements Enzyme Activation Event Future Generations Genes Genetic Recombination Holoenzymes Human IgE Immune response Immunity Immunoglobulin A Immunoglobulin Class Switching Immunoglobulin G Immunoglobulin M Immunoglobulin Somatic Hypermutation Immunoglobulin Switch Recombination Immunoglobulins Immunologic Deficiency Syndromes In Vitro Knock-in Mouse Lead Lesion Light Lymphomagenesis Malignant Neoplasms Mature B-Lymphocyte Measures Mediating Modeling Mus Mutant Strains Mice Mutation Oncogenes Patients Phosphoproteins Phosphorylation Phosphorylation Site Phosphotransferases Physiological Play Point Mutation Post-Translational Protein Processing Predisposition Process Proteins Public Health Reaction Recruitment Activity Repetitive Sequence Reporting Research Proposals Role Series Serine Single-Stranded DNA Specificity Testing Uridine activation-induced cytidine deaminase antigen binding base cofactor constant region gene design genetic regulatory protein in vivo insight mutant novel prevent protein activation repaired replication factor A research study stem

项目摘要

PROJECT SUMMARY To mount an optimum immune response, mature B lymphocytes undergo two genetic alterations in the forms of class switch recombination (CSR) and somatic hypermutation (SHM). CSR leads to the production of antibodies of various isotypes (IgG, IgE, IgA) while SHM results in the generation of antibody molecules with a much higher affinity for antigens. The B cell specific protein AID (activation induced deaminase) is essential to both processes. AID initiates CSR and SHM by deaminating cytidines within transcribed regions of the immunoglobulin locus. These lesions are then converted into point mutations during SHM or into DNA double strand breaks that serve as obligatory intermediates during CSR. Inactivation of AID leads to human immunodeficiency syndromes (Hyper-IgM2) where patients suffer from profound susceptibility to bacterial infections. On the other hand, deregulation of AID converts it into a general mutator and leads to mutations and translocations of oncogenes that have been implicated in mature B cell lymphomagenesis. An understanding of the processes that regulate AID activity is thus of utmost importance. The overall objective of this research proposal is to elucidate the mechanism by which AID activity is regulated during CSR and SHM. Recent studies have shown that protein kinase A (PKA) phosphorylates AID in vitro to activate its ability to bind its cofactor, the single-stand DNA binding protein Replication Protein A and mediate deamination of transcribed DNA substrates. To elucidate the role of AID phosphorylation in vivo, mice with a mutation in the AID phosphorylation site will be generated and analyzed for CSR and SHM. The mutant mouse will also be used in cellular and biochemical assays to delineate the function of phosphorylated AID in CSR and SHM. Finally, existing PKA mutants will be analyzed to test the hypothesis that AID phosphorylation by PKA is itself a highly regulated event and could potentially contribute to AID target specificity. Successful completion of the projects outlined in this proposal will provide mechanistic insights into reactions central to immunity and how aberrations in such physiological reactions can cause mature B cell tumors.

项目概要为了产生最佳的免疫反应，成熟的 B 淋巴细胞在类转换重组（CSR）和体细胞超突变（SHM）的形式。企业社会责任导致生产各种同种型的抗体（IgG、IgE、IgA），而 SHM 会产生具有对抗原的亲和力要高得多。 B 细胞特异性蛋白 AID（激活诱导脱氨酶）对于两个过程。 AID 通过使转录区域内的胞苷脱氨基来启动 CSR 和 SHM 免疫球蛋白位点。然后这些病变在 SHM 期间转化为点突变或 DNA 双链断裂在 CSR 过程中充当必需的中间体。 AID失活会导致人类免疫缺陷综合征（Hyper-IgM2），患者对细菌高度易感感染。另一方面，AID 的放松管制会将其转化为通用突变子并导致突变和与成熟 B 细胞淋巴瘤发生有关的癌基因易位。一种理解因此，规范 AID 活动的流程至关重要。本研究的总体目标该提案旨在阐明企业社会责任和健康管理期间对援助活动进行监管的机制。最近的研究表明，蛋白激酶A（PKA）在体外磷酸化AID，激活其与其结合的能力辅因子，单链 DNA 结合蛋白复制蛋白 A，介导转录的脱氨基作用 DNA 底物。为了阐明 AID 磷酸化在体内的作用，AID 突变的小鼠将生成磷酸化位点并分析 CSR 和 SHM。突变小鼠也将被用于细胞和生化测定来描述磷酸化 AID 在 CSR 和 SHM 中的功能。最后，将分析现有的 PKA 突变体，以检验 AID 被 PKA 磷酸化本身就是一种高度受监管的事件，并可能有助于 AID 目标特异性。项目顺利完成该提案中概述的内容将提供对免疫至关重要的反应的机制见解以及如何此类生理反应的异常可导致成熟B细胞肿瘤。