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：类开关DNA重组对 同型在B细胞中切换，并且似乎也参与染色体 某些癌基因的易位。但是，对切换知之甚少 机制。所有H链抗体上游的串联重复序列 恒定区域基因通常被认为在 靶向和/或类开关重组的机制。我们使用了基因 目标以删除与开关区域相关的串联重复 与小鼠中的Cu常数区域。令人惊讶的是，这些突变小鼠仍然 尽管该过程的效率是 适度减少。我们的发现表明SU。串联重复不是 切换过程所需的。当前的提议旨在扩展我们的 初步结果分析类开关DNA的几个方面 重组。据报道，DNA不匹配修复（MMR）酶也 影响效率并加入类切换的站点选择。我们希望 研究Su串联重复和MMR之间的相互关系 开关过程中的酶通过产生缺乏的双突变动物 SU重复和特定的单个MMR蛋白。第二，我们想 确定RNA：DNA复合物是否可以在缺乏的ASU JH-CU内含子中形成 串联重复元素，以探讨先前建议的重要性 这些复合物在切换过程中。最后，调查亲戚 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，我们将通过基因靶向突变产生 缺乏SA或SU和SA的小鼠。这些切换分析 突变小鼠应指示下游S区域是否更大 正如控制重组过程重要的重要 一些人工开关底物的研究。