Role of RAG1 autoubiquitination in V(D)J recombination.
Role of RAG1 autoubiquitination in V(D)J recombination.
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RAG1 自动泛素化在 V(D)J 重组中的作用。
DOI：
10.1073/pnas.1510464112
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发表时间：
2015
影响因子：
11.1
通讯作者：
Gellert,Martin
中科院分区：
文献类型：
--
作者：
Singh,SamarendraK;Gellert,Martin
脊椎动物中的IG和T细胞受体基因的可变结构域通过V（D）J重组过程从基因片段组装。RAG 1-RAG 2重组酶（RAG 1/2）通过在重组信号序列（RSS）及其相邻基因片段的边界切割DNA来启动这种重组。RAG 1蛋白还已知含有泛素E3连接酶活性，位于N-末端区域，其对于基本重组反应不是严格需要的，但有助于调节重组。分离的E3连接酶结构域较早被证明在相邻的RAG 1序列中泛素化一个位点。在这里，我们表明，在这个特定的残基（K233）的全长RAG 1的autoubiquitination的结果在一个大的增加RAG 1/2的DNA切割。泛素化位点的突变阻断消除了这种效应，并抑制了小鼠细胞中测试底物的重组。因此，RAG 1自身的泛素连接酶活性可促进RAG 1的泛素化，其在控制V（D）J重组活性水平中起重要作用。
The variable domains of Ig and T-cell receptor genes in vertebrates are assembled from gene fragments by the V(D)J recombination process. The RAG1–RAG2 recombinase (RAG1/2) initiates this recombination by cutting DNA at the borders of recombination signal sequences (RSS) and their neighboring gene segments. The RAG1 protein is also known to contain a ubiquitin E3 ligase activity, located in an N-terminal region that is not strictly required for the basic recombination reaction but helps to regulate recombination. The isolated E3 ligase domain was earlier shown to ubiquitinate one site in a neighboring RAG1 sequence. Here we show that autoubiquitination of full-length RAG1 at this specific residue (K233) results in a large increase of DNA cleavage by RAG1/2. A mutational block of the ubiquitination site abolishes this effect and inhibits recombination of a test substrate in mouse cells. Thus, ubiquitination of RAG1, which can be promoted by RAG1’s own ubiquitin ligase activity, plays a significant role in governing the level of V(D)J recombination activity.