REGULATION OF V(D)J RECOMBINATION IN CELL CYCLE AND IN DEVELOPMENT

细胞周期和发育中 V(D)J 重组的调节

• 批准号: 7049163
• 负责人: STEPHEN V DESIDERIO
• 金额: $ 17.25万
• 依托单位: JOHNS HOPKINS UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2005
• 资助国家: 美国
• 起止时间: 2005-12-01 至 2010-11-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7049163
• 关键词: DNA; cell cycle; neoplasm /cancer

Lymphoid tumors are the most common malignancies in children, and aberrant chromosomal rearrangements are implicated in the generation of many of these cancers. The long term goals of this project remain to understand the mechanisms underlying genomic plasticity and its control in the developing immune system. The variable regions of antigen receptor polypeptide chains are encoded in separate DNA segments that are brought together during lymphoid development by V(D)J recombination, a form of site-specific DNA rearrangement. The proteins RAG-1 and RAG-2 initiate V(D)J recombination by cleaving participating gene segments at specific recombination signal sequences (RSSs). Completion of recombination employs the cellular machinery for non-homologous DNA end joining (NHEJ), a form of DNA double strand break repair (DSBR). V(D)J recombination is coupled to the cell cycle by the periodic destruction of RAG-2. Coordination of V(D)J recombinase activity with NHEJ is required for the maintenance of genomic integrity; when RAG-induced DNA breaks are improperly sensed and repaired, the resulting genomic rearrangements can give rise to lymphoid tumors. Correspondingly, a growing body of evidence indicates that aberrant V(D)J recombination contributes to the pathogenesis of lymphoid malignancies. Renewed funding is requested for continued study of mechanisms that regulate V(D)J recombination and the contributions of these mechanisms to suppression of tumorigenesis. The proposal has the following aims: (1) to define a detailed mechanism by which V(D)J recombination is linked to the cell cycle, by a combination of biochemical analysis and validation in vivo; (2) to understand the physiologic consequences of uncoupling V(D)J recombination from cell cycle, through the use of mice expressing forms of RAG-2 that escape regulation; (3) to elucidate the mechanism by which V(D)J recombination intermediates are disassembled, through development of a cell-free system; and (4) to build a novel, regulable system to study the feedback control of V(D)J recombination, employing chemical rescue of mutant kinase activites in mouse B cell progenitors.

淋巴样肿瘤是儿童最常见的恶性肿瘤，染色体异常 重排与许多此类癌症的发生有关。这样做的长期目标是 项目仍然是为了了解基因组可塑性的潜在机制及其在 发展免疫系统。抗原受体多肽链的可变区编码在 V(D)J在淋巴发育过程中聚集在一起的分离DNA片段 重组，一种特定部位的DNA重排形式。蛋白RAG-1和RAG-2启动 在特定重组信号序列上切割参与基因片段的V(D)J重组 (RSS)。重组的完成使用了非同源DNA末端的细胞机制 连接(NHEJ)，DNA双链断裂修复(DSBR)的一种形式。V(D)J复合耦合到 RAG-2的周期性破坏对细胞周期的影响。V(D)J重组酶活力与 NHEJ是维持基因组完整性所必需的；当RAG诱导的DNA断裂是 如果检测和修复不当，由此产生的基因组重排可能会导致淋巴样肿瘤。 相应地，越来越多的证据表明，异常的V(D)J重组有助于 淋巴系恶性肿瘤的发病机制。申请续期资金以继续研究 调节V(D)J重组的机制及其对抑制的贡献 关于肿瘤发生的研究。这项建议的目的如下：(1)界定一个详细的机制，借以 通过生化分析和验证相结合，V(D)J重组与细胞周期有关 在体内；(2)了解V(D)J从细胞中解偶联重组的生理后果 通过使用表达形式的逃避调节的RAG-2的小鼠；(3)阐明 V(D)J复合中间体的分解机制，通过发展一种 建立了一种新的、可调节的系统来研究V(D)J的反馈控制 重组，采用化学拯救小鼠B细胞前体细胞中突变的激酶活性。