V(D)J recombination intermediates and non-standard products in XRCC4-deficient cells
V(D)J recombination intermediates and non-standard products in XRCC4-deficient cells
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DOI：
10.1093/nar/26.16.3769
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发表时间：
1998-08-15
影响因子：
14.9
通讯作者：
Roth, DB
中科院分区：
文献类型：
--
作者：
Han, JO;Erskine, LA;Roth, DB
在淋巴细胞发育过程中，V（D）J重组组装免疫球蛋白（IG）和T细胞受体（TCR）基因片段。RAG-1和RAG-P蛋白质引发双链DNA断裂（DSB），所述双链DNA断裂邻近IG和TCR基因区段。断裂的末端由DSB修复机制连接，该机制包括XRCC 4蛋白。虽然XRCC 4对于DSB修复和V（D）J重组都是必需的，但该蛋白的功能仍然是个谜。由于从XRCC 4缺陷细胞中分离的罕见V（D）J重组产物通常显示出过度核苷酸丢失的证据，因此假设XRCC 4可能具有保护断裂DNA末端的功能。在这里，我们报告的第一次检查的V（D）J重组中间体在XRCC 4缺陷细胞。我们发现在XRCC 4缺失的细胞中，信号末端和编码末端这两种类型的中间体都是丰富的，而且信号末端是全长的。我们还发现在XRCC 4缺失的细胞中，交替的V（D）J重组产物，即杂交接头，以正常的效率形成，而没有过度缺失。这些数据表明，在XRCC 4缺陷细胞中，V（D）J重组产物的形成受损不是由于重组中间体的过度降解。讨论了XRCC 4在连接反应中的潜在作用。
V(D)J recombination assembles immunoglobulin (Ig) and T cell receptor (TCR) gene segments during lymphocyte development. Recombination is initiated by the RAG-1 and RAG-P proteins, which introduce double-stranded DNA breaks (DSB) adjacent to the Ig and TCR gene segments. The broken ends are joined by the DSB repair machinery, which includes the XRCC4 protein, While XRCC4 is essential for both DSB repair and V(D)J recombination, the functions of this protein remain enigmatic. Because the rare V(D)J recombination products isolated from XRCC4-deficient cells generally show evidence of excessive nucleotide loss, it was hypothesized that XRCC4 may function to protect broken DNA ends. Here we report the first examination of V(D)J recombination intermediates in XRCC4-deficient cells. We found that both types of intermediates, signal ends and coding ends, are abundant in the absence of XRCC4, Furthermore, the signal ends are full length, We also showed that alternative V(D)J recombination products, hybrid joints, form with normal efficiency and without excessive deletion in XRCC4-deficient cells. These data indicate that impaired formation of V(D)J recombination products in XRCC4-deficient cells does not result from excessive degradation of recombination intermediates. Potential roles of XRCC4 in the joining reaction are discussed.