FUNCTIONS OF ANTIBODY SWITCH REGIONS

抗体开关区域的功能

• 批准号: 6624520
• 负责人: ERIK SELSING
• 金额: $ 20.88万
• 依托单位: TUFTS UNIVERSITY BOSTON
• 依托单位国家: 美国
• 财政年份: 2000
• 资助国家: 美国
• 起止时间: 2000-12-15 至 2004-11-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6624520
• 关键词: B lymphocyte; DNA repair; antibody formation; gene rearrangement; gene targeting; genetically modified animals; immunoglobulin genes; laboratory mouse

APPLICANT'S DESCRIPTION: Class switch DNA recombinations are important for isotype switching in B cells and also appear to be involved in chromosomal translocations of some oncogenes. However, little is known about the switching mechanism. Tandemly-repeated sequences located upstream of all H-chain antibody constant regions genes have generally been thought to be important in the targeting and/or the mechanism of class switch recombination. We have used gene targeting to delete the tandem repeats from the switch (S) region associated with the Cu constant region in mice. Surprisingly, these mutant mice are still able to undergo isotype switching, although the efficiency of the process is modestly reduced. Our findings indicate that the Su. tandem repeats are not required for the switching process. The current proposal seeks to extend our preliminary results to analyze several aspects of class switch DNA recombination. It has been reported that DNA mismatch repair (MMR) enzymes also affect the efficiency and joining site selection of class switching. We wish to investigate the mutual relationships between the Su tandem repeats and MMR enzymes in the switching process by producing double-mutant animals that lack both the Su repeats and specific individual MMR proteins. Second, we want to determine whether RNA:DNA complexes can form in the ASu JH-Cu intron that lacks the tandem repeat element to explore the previously suggested importance of these complexes in the switching process. Finally, to investigate the relative importance of the Su tandem repeats, in comparison to the tandem repeats found associated with downstream CH genes, we will produce, by gene targeting, mutant mice that lack either Sa or both Su and Sa. Analysis of switching in these mutant mice should indicate whether downstream S regions are much more important in controlling the recombination process as has been suggested by some studies of artificial switch substrates.

申请人的描述：类别转换 DNA 重组对于 B 细胞中的同型转换，似乎也参与染色体 一些癌基因的易位。然而，人们对这种切换知之甚少 机制。串联重复序列位于所有 H 链抗体的上游 恒定区基因通常被认为在 靶向和/或类别转换重组的机制。我们用了基因 目标是从关联的开关 (S) 区域删除串联重复序列 与小鼠体内的 Cu 恒定区。令人惊讶的是，这些突变小鼠仍然 能够进行同种型转换，尽管该过程的效率较低 适度减少。我们的研究结果表明，苏。串联重复不是 切换过程所需的。当前的提案旨在扩展我们的 分析类别转换 DNA 几个方面的初步结果 重组。据报道，DNA错配修复（MMR）酶也 影响类切换的效率和加入站点的选择。我们希望 研究Su串联重复序列与MMR之间的相互关系 通过产生缺乏酶的双突变动物来控制转换过程中的酶 Su 重复序列和特定的单个 MMR 蛋白。其次，我们想要 确定 RNA:DNA 复合物是否可以在缺乏的 ASu JH-Cu 内含子中形成 串联重复元件探索先前建议的重要性 这些复合物在转换过程中。最后，调查亲属 与发现的串联重复相比，Su串联重复的重要性 与下游CH基因相关，我们将通过基因打靶产生突变体 缺乏 Sa 或同时缺乏 Su 和 Sa 的小鼠。对这些开关的分析 突变小鼠应表明下游 S 区域是否更多 正如所建议的，对于控制重组过程很重要 人工开关基质的一些研究。