Regulation and Dysregulation of Antibody Diversification

抗体多样化的调节和失调

• 批准号: 8129487
• 负责人: MATTHEW STROUT
• 金额: $ 17.44万
• 依托单位: YALE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-09-10 至 2014-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8129487
• 关键词: Affect; Alternative Splicing; Animals; Antibodies; B lymphoid malignancy; B-Cell Lymphomas; B-Lymphocytes; Base Excision Repairs; Biology; Cell Line; Cellular Stress; Chromosomal Instability; Chronic Lymphocytic Leukemia; Cytidine; Cytosine; DNA; DNA Repair; DNA Repair Pathway; DNA-Directed DNA Polymerase; Data; Deamination; Development; Disease; Equilibrium; Event; Frequencies; Gene Expression; Gene Mutation; Genes; Genetic; Genome; Genome Stability; Genomic Instability; Genomics; Genotoxic Stress; Goals; Guanine; Hepatitis C virus; Human; Immune; Immunoglobulin Class Switching; Immunoglobulin Genes; Immunoglobulin Somatic Hypermutation; Immunoglobulin Switch Recombination; Immunoglobulins; Infection; Knockout Mice; Left; Lesion; Malignant - descriptor; Malignant lymphoid neoplasm; Mediating; Mismatch Repair; Modeling; Molecular; Molecular Profiling; Mus; Mutate; Mutation; Nature; Pathogenesis; Pathway interactions; Pattern; Phase; Physiological; Play; Point Mutation; Principal Investigator; Printing; Proto-Oncogenes; Regulation; Research; Research Proposals; Role; Specimen; Structure of germinal center of lymph node; T-Lymphocyte; Testing; Transgenic Mice; Uracil; Variant; Virus Diseases; activation-induced cytidine deaminase; foot; infected B cell; insight; mouse model; neoplastic; repaired; stressor; transition mutation

DESCRIPTION (provided by applicant): Activation-Induced cytidine deaminase (AID) is expressed in germinal center B cells and is required for somatic hypermutation (SHM) and class switch recombination (CSR) of immunoglobulin genes. Aberrant targeting of AID to proto-oncogenes has also been implicated in the pathogenesis of B cell malignancies. AID has the potential to trigger mutations and chromosome instability throughout the genome but many genes are protected by high-fidelity DNA repair of AID-mediated events. The mechanisms responsible for guiding AID to its genetic target and determining whether a mutation will be repaired in a high-fidelity or low-fidelity manner are not understood. The central hypothesis underlying this proposal is that B cells have a specific mechanism for maintaining genomic stability in the face of SHM and CSR and that events leading to the breakdown of this mechanism contribute to AID-mediated genomic instability and malignant transformation. Here, a combination of animal and cell line models will be used to study the dynamic relationship of AID activity and DNA repair under both normal and neoplastic conditions. In Specific Aim 1, mouse models of AID expression and DNA repair will be used to identify the lineage-specific mechanism that protects the B cell genome during SHM and investigate the contribution of AID-associated DNA repair pathways to the pathogenesis of lymphoid malignancy. In Specific Aim 2, exogenous cellular stressors that perturb the balance of high-fidelity and low-fidelity DNA repair following AID activity will be characterized and used as a means for identifying factors that regulate the mutation threshold and in an actively mutating B cell. In Specific Aim 3, the role of AID in the pathogenesis of B cell chronic lymphocytic leukemia (B-CLL) will be defined in a mouse model of this disease and the functional nature of AID will be characterized in human B-CLL cell lines and primary B-CLL specimens. We anticipate that this research will provide insight into the basic mechanism that regulates immune diversification in B cells and serve a long-term objective of identifying the molecular steps involved in the pathogenesis of lymphoid malignancy.

描述（由申请人提供）：激活诱导的胞苷脱氨酶（AID）在生发中心B细胞中表达，是免疫球蛋白基因的体细胞超突变（SHM）和类转换重组（CSR）所必需的。异常靶向对原始基因的靶向也与B细胞恶性肿瘤的发病机理有关。 AID具有在整个基因组中触发突变和染色体不稳定性的潜力，但许多基因受到辅助介导的事件的高保真DNA修复的保护。尚不了解负责指导其遗传靶标的辅助的机制，并确定是否以高保真或低保真方式修复突变。该提议的基本假设是，B细胞在面对SHM和CSR时具有保持基因组稳定性的特定机制，并且导致这种机制崩溃的事件有助于AID介导的基因组不稳定和恶性转化。在这里，将使用动物和细胞系模型的组合来研究在正常和肿瘤条件下援助活动和DNA修复的动态关系。在特定的目标1中，将使用辅助表达和DNA修复的小鼠模型来识别SHM期间保护B细胞基因组的谱系特异性机制，并研究与AID相关的DNA修复途径对淋巴性恶性肿瘤发病机理的贡献。在特定的目标2中，将表征高保真性和低效率DNA修复平衡的外源细胞应激源，并将其用作识别调节突变阈值和主动突变B细胞的因子的手段。在特定的目标3中，辅助在B细胞慢性淋巴细胞性白血病（B-CLL）中的作用将在该疾病的小鼠模型中定义，辅助的功能性质将在人B-CLL细胞系和原发性B-CLL标本中进行表征。我们预计，这项研究将提供对调节B细胞免疫多样化的基本机制的见解，并具有识别淋巴性恶性发病机理的分子步骤的长期目标。