Usuda S, Takemori T, Matsuoka M, Shirasawa T, Yoshida K, Mori A, Ishizaka K, Sakano H
Department of Molecular and Cell Biology, University of California, Berkeley 94720.
EMBO J. 1992 Feb;11(2):611-8. doi: 10.1002/j.1460-2075.1992.tb05093.x.
Circular DNA resulting from V gene replacement was studied with an A-MuLV transformed cell line containing ablts. This cell line undergoes V gene replacement at elevated temperatures in the immunoglobulin (Ig) heavy chain (H) gene. Examination of circular DNA revealed that a heptamer-related sequence (TACTGTG) within the coding region of VDJ was joined to the recombination signal sequence (RSS) of a germline VH segment. This provides direct evidence for a intramolecular DNA deletion mechanism for V gene replacement. In the pre-B cell line as well as in in vivo lymphocytes, unusual circular DNAs were found which were structurally similar to the V gene replacement circles. They represented excision products of the deletion type recombination between one complete RSS and a heptamer-like sequence in the Ig H region.
利用含有ablts的A-MuLV转化细胞系研究了由V基因置换产生的环状DNA。该细胞系在免疫球蛋白（Ig）重链（H）基因中，在高温下会发生V基因置换。对环状DNA的检测表明，VDJ编码区内一个七聚体相关序列（TACTGTG）与种系VH片段的重组信号序列（RSS）相连。这为V基因置换的分子内DNA缺失机制提供了直接证据。在前B细胞系以及体内淋巴细胞中，发现了结构上与V基因置换环相似的异常环状DNA。它们代表了Ig H区域中一个完整RSS与一个七聚体样序列之间缺失型重组的切除产物。
