Contribution of VH gene replacement to the primary B cell repertoire
Contribution of VH gene replacement to the primary B cell repertoire
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DOI：
10.1016/s1074-7613(03)00170-5
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发表时间：
2003-07-01
期刊：
影响因子：
32.4
通讯作者：
Cooper, MD
中科院分区：
文献类型：
--
作者：
Zhang, ZX;Zemlin, M;Cooper, MD
已经提出V-H置换作为修饰不需要的抗体特异性的一种方式，但是在没有动态细胞模型的情况下，对这种机制的分析受到限制。我们描述了一个人细胞系，自发地经历了一系列的V-H基因置换介导的隐蔽重组信号序列（cRSS）位于V-H基因的3'端附近。在V-H置换过程中，还原活化基因产物RAG-1和RAG-2结合并切割cRSS以产生DNA缺失环。通过鉴定IgH序列中的V-H置换“足迹”和未成熟B细胞中V-H cRSS位点处的双链DNA断裂，揭示了VH置换对正常库发育的贡献。令人惊讶的是，被替换的V-H基因的残留3'序列为CDR 3区贡献了带电荷的氨基酸，这是自身反应性抗体的标志。
V-H replacement has been proposed as one way to modify unwanted antibody specificities, but analysis of this mechanism has been limited without a dynamic cellular model. We describe a human cell line that spontaneously undergoes serial V-H gene replacement mediated by cryptic recombination signal sequences (cRSS) located near the 3' end of V-H genes. Recombination-activating gene products, RAG-1 and RAG-2, bind and cleave the cRSS to generate DNA deletion circles during the V-H replacement process. A VH replacement contribution to normal repertoire development is revealed by the identification of V-H replacement "footprints" in IgH sequences and double-stranded DNA breaks at V-H cRSS sites in immature B cells. Surprisingly, the residual 3' sequences of replaced V-H genes contribute charged amino acids to the CDR3 region, a hallmark of autoreactive antibodies.