Chromosomal reinsertion of broken RSS ends during T cell development.
Chromosomal reinsertion of broken RSS ends during T cell development.
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DOI：
10.1084/jem.20070583
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发表时间：
2007-10-01
期刊：
影响因子：
--
通讯作者：
Schlissel MS
中科院分区：
文献类型：
--
作者：
Curry JD;Schulz D;Guidos CJ;Danska JS;Nutter L;Nussenzweig A;Schlissel MS
V(D)J重组酶在体内和体外都能催化DNA转座和转位。由于淋巴系恶性肿瘤含有涉及抗原受体和原癌基因位点的染色体易位，因此了解重组酶所犯的“错误”类型是至关重要的。使用一种新设计的方法，我们在小鼠胸腺细胞和脾细胞基因组β样本中鉴定了48个独特的TCRDNA重组信号序列末端插入。这些事件中有近一半针对的是类似RSS的“神秘”元素。我们在任何情况下都没有检测到靶点复制，这是重组酶介导的体外转座的标志。相反，这些插入很可能是由真正的RSS和隐蔽的RSS之间的V(D)J重组或通过类似V(D)J重组的机制将信号环插入到染色体上所致。虽然野生型、P53、P53 x SCID、H 2AX和ATM突变胸腺细胞都显示出相似水平的RSS末端插入，但核心RAG2突变胸腺细胞发生此类事件的频率要高7倍。因此，RAG2的非核心结构域限制了V(D)J重组的错误定位对基因组完整性的威胁程度。
The V(D)J recombinase catalyzes DNA transposition and translocation both in vitro and in vivo. Because lymphoid malignancies contain chromosomal translocations involving antigen receptor and protooncogene loci, it is critical to understand the types of “mistakes” made by the recombinase. Using a newly devised assay, we characterized 48 unique TCRβ recombination signal sequence (RSS) end insertions in murine thymocyte and splenocyte genomic DNA samples. Nearly half of these events targeted “cryptic” RSS-like elements. In no instance did we detect target-site duplications, which is a hallmark of recombinase-mediated transposition in vitro. Rather, these insertions were most likely caused by either V(D)J recombination between a bona fide RSS and a cryptic RSS or the insertion of signal circles into chromosomal loci via a V(D)J recombination-like mechanism. Although wild-type, p53, p53 x scid, H2Ax, and ATM mutant thymocytes all showed similar levels of RSS end insertions, core-RAG2 mutant thymocytes showed a sevenfold greater frequency of such events. Thus, the noncore domain of RAG2 serves to limit the extent to which the integrity of the genome is threatened by mistargeting of V(D)J recombination.
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影响因子：
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