STUDIES OF IMMUNOGLOBULIN GENE REARRANGEMENT

抗原受体基因重排(V(D)J重组)研究进展 描述了被识别和重组的信号序列 产品，但没有关于反应进展的信息。 现在有可能检测到断裂的DNA分子可能是 这一重组的中间体。 在幼年小鼠的胸腺中，T细胞受体Delta位点 (TCRDelta)正在积极重新排列，双链断裂在 Southern杂交检测到Ddelta2和Jdelta1基因座。关于 2%的DNA被破坏--这是一个非常高的比例。坏的 分子只在胸腺中发现，而在TCRDelta的其他组织中没有 并未进行重新安排。两个不同的目的中，应该是 由每个断点产生，只能检测到一个(信号端)。这个 可以更快地连接编码端。这些结果提供了第一个 直接支持V(D)J复合的破裂-团聚模型。 在相关工作中，已经开发出一种物理分析方法，可以使 直接检测V(D)J连接到质粒底物，而不需要 进行生物浓缩。

Previous work on antigen receptor gene rearrangement (V(D)J recombination) has described the signal sequences that are recognized and the recombined products, but there was no information about the progress of the reaction. It has now become possible to detect broken DNA molecules that may be intermediates in this recombination. In the thymus of young mice, where the T cell receptor delta locus (TCRdelta) is being actively rearranged, double-strand breaks at the Ddelta2 and Jdelta1 loci are readily detected by Southern blotting. About 2% of the DNA's is broken - this is a remarkably high proportion. Broken molecules are found only in thymus and not in other tissues where TCRdelta is not undergoing rearrangement. Of the two different ends that should be generated by each break, only one (the signal end) could be detected. The coding ends may be joined more rapidly. These results provide the first direct support for a breakage - reunion model of V(D)J recombination. In related work, a physical assay has been developed that allows the direct detection of V(D)J joining in plasmid substrates, without the need for a biological enrichment.