Mismatch repair in V region mutation and isotype switching

V区突变和同种型转换中的错配修复

• 批准号: 7579404
• 负责人: MATTHEW D SCHARFF
• 金额: $ 32.46万
• 依托单位: ALBERT EINSTEIN COLLEGE OF MEDICINE
• 依托单位国家: 美国
• 财政年份: 2003
• 资助国家: 美国
• 起止时间: 2003-07-01 至 2013-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7579404
• 关键词: ATP phosphohydrolase; Affinity; Affinity Chromatography; Antibodies; Antigens; B cell differentiation; B-Cell Development; B-Cell Lymphomas; B-Lymphocytes; Base Excision Repairs; Base Pairing; Biochemical; Cell Cycle Stage; Cells; Characteristics; Complex; DNA; Data; Defect; EXO1 gene; Excision; G1 Phase; Generation of Antibody Diversity; Genes; Genetic; Genetic Recombination; Genome; Genome Stability; Immunoglobulin Class Switching; Immunoglobulin Genes; Immunoglobulin Somatic Hypermutation; Immunoglobulin Switch Recombination; Immunoglobulin Variable Region; Immunoglobulins; Immunoprecipitation; Induced Mutation; Infection; Investigation; Knock-in Mouse; Knock-out; Lead; Lymphoma; Lymphomagenesis; MLH1 gene; MSH2 gene; MSH6 gene; Malignant - descriptor; Mediating; Mismatch Repair; Missense Mutation; Molecular Analysis; Mus; Mutant Strains Mice; Mutate; Mutation; Organism; PMS2 gene; Phase; Phenotype; Play; Polymerase; Process; Production; Progress Reports; Proteins; Recruitment Activity; Replication-Associated Process; Rest; Role; Single-Stranded DNA; Somatic Mutation; Staging; Stretching; Structure of germinal center of lymph node; T-Cell Lymphoma; T-Lymphocyte; Work; activation-induced cytidine deaminase; base; cell type; endonuclease; pathogen; prevent; protein protein interaction; public health relevance; repaired; tumor

DESCRIPTION (provided by applicant): Germinal center B cells undergo a high rate of somatic mutation and recombination of their immunoglobulin genes that is responsible for the affinity maturation and isotype switching that generates protective antibodies. These processes are initiated by activation induced cytidine deaminase which generates G:U mismatches that are processed by replication, base excision repair and mismatch repair to produce the mutations required for somatic hypermutation of antibody variable and switch regions. Mismatch repair is responsible for ~60% of the total mutations and most of the mutations in A:T bases that lead to production of more effective antibodies. While mismatch repair normally maintains the integrity and stability of the genome, at the Ig gene it mediates extensive mutation and recombination. Here we propose to examine how germinal center B cells use mismatch repair to recruit error prone repair to specific regions of the immunoglobulin genes while continuing to maintain genomic stability in the rest of genome and to examine role of mismatch repair in the B cell lymphomagenesis. We will do this by: 1) determining how MSH6 and the other mismatch repair proteins interact with PCNA to recruit error prone repair to the immunoglobulin variable and switch regions, but not to other genes in mutating and switching germinal center B cells; 2) comparing the interactions of the mismatch repair proteins with each other and with other proteins in mutating and switching B cells and with those interactions in other types of cells; and 3) examining the characteristics of the lymphomas that arise in MSH6 deficient and mutant mice in order to understand how MSH6 protects B cells from lymphomagenesis. PUBLIC HEALTH RELEVANCE: To protect us from pathogenic organisms, it is necessary for us to produce antibodies to every possible antigen and to rapidly change those antibodies as the pathogen changes. We do this by introducing many mutations into the genes that encode the antibody molecules as we respond to infection and this genetic instability is accomplished mostly through a process called mismatch repair. We will use mice that have genetic defects in mismatch repair to examine how the generation of antibody diversity is accomplished.

描述（由申请人提供）：生发中心B细胞经历了高体突变率和其免疫球蛋白基因的重组，该基因负责产生保护性抗体的亲和力成熟和同型转换。这些过程是通过激活诱导的胞苷脱氨酶引发的，胞苷脱氨酶产生了通过复制，基础切除修复和不匹配修复来处理的G：u不匹配，以产生抗体可变和开关区域的体细胞超痕迹所需的突变。不匹配修复造成了总突变的约60％，并且在A：T碱基中大多数突变导致产生更有效的抗体。尽管不匹配修复通常保持基因组的完整性和稳定性，但在IG基因下，它介导了广泛的突变和重组。在这里，我们建议研究生发中心B细胞如何使用不匹配修复来募集误差易于修复免疫球蛋白基因的特定区域，同时继续在基因组的其他基因组中保持基因组稳定性，并检查不匹配修复在B细胞淋巴细胞中的作用。我们将通过：1）确定MSH6和其他不匹配修复蛋白与PCNA相互作用，以募集误差易于修复免疫球蛋白变量和开关区域，但在突变和切换生发中心B细胞时不适合其​​他基因； 2）将不匹配修复蛋白与彼此以及其他蛋白质的相互作用在突变和切换B细胞中以及其他类型的细胞中的相互作用进行比较； 3）检查在MSH6缺乏和突变小鼠中出现的淋巴瘤的特征，以了解MSH6如何保护B细胞免受淋巴细胞的影响。公共卫生相关性：为了保护我们免受致病生物的侵害，我们有必要对每种可能的抗原产生抗体，并随着病原体的变化而迅速改变这些抗体。我们通过将许多突变引入对感染反应时编码抗体分子的基因中来做到这一点，并且这种遗传不稳定性主要是通过称为不匹配修复的过程来实现的。我们将使用在不匹配修复中具有遗传缺陷的小鼠来检查如何完成抗体多样性的产生。