循环DNA是通过免疫球蛋白类开关重组合成切除的
T Iwasato1, A Shimizu, T Honjo
1Department of Biophysics, Faculty of Science, Kyoto University, Japan.
Cell
|July 13, 1990
概括
外染色体循环DNA分析揭示了免疫球蛋白类切换的新型机制. 这个过程涉及DNA的循环和循环化,解释了mu-gamma 1切换是如何发生的.
科学领域:
- 免疫学 免疫学 免疫学
- 分子生物学分子生物学
- 遗传学 是一个遗传学.
背景情况:
- 免疫球蛋白类别的切换是一个关键的适应性免疫过程.
- 在类切换过程中,S mu和S gamma 1区域的结合背后的机制尚未完全理解.
- 外染色体圆形DNA (eccDNA) 越来越多地被认为是其在基因组动态中的作用.
研究的目的:
- 调查eccDNA在免疫球蛋白重链类别切换中的作用.
- 为了确定mu-gamma 1类切换的分子机制.
- 描述S mu和S gamma 1连接所涉及的重组位点.
主要方法:
- 从成年小鼠脏细胞中净化eccDNA.
- 从eccDNA中克隆BamHI片段,将其转化为菌体载体.
- 使用C mu和S gamma 1探针对菌体克隆进行查.
- 在S mu-S gamma 1+克隆中识别和测序重组断点.
主要成果:
- 52个S mu+S gamma 1+克隆从140万个选中被识别出来.
- 六个克隆显示了5'到3'方向的化S玛1和S序列.
- 再组合地点位于S mu和S gamma 1的中心重复序列中.
- 重组部位的常见序列最多长2个基对,排除同源重组.
结论:
- Mu-玛1类切换可以通过染色体DNA的循环和切割发生,形成一个圆形的中间体.
- 这种机制为免疫球蛋白类别切换中的非同类重组途径提供了直接证据.
- eccDNA在促进免疫球蛋白类切换重组中发挥着重要作用.
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