Klein S, Sablitzky F, Radbruch A
EMBO J. 1984 Nov;3(11):2473-6. doi: 10.1002/j.1460-2075.1984.tb02158.x.
Immunoglobulin (Ig) gene promotors are active only in cells of the B-lymphocyte lineage. Transfection experiments have shown that this is due in part to tissue specific 'activating' DNA sequences, so called enhancers. It is not entirely clear whether these sequences are necessary for initial activation or also for maintenance of transcription of a gene. We describe here the isolation and characterisation of a mouse hybridoma cell line that has deleted in vitro the 'activating' sequence from the active IgH locus, the only IgH locus it contains. Nevertheless, Ig heavy chain production of the variant cell is not impaired and remains comparable with that of other hybridoma cells. Therefore, a high rate of Ig heavy chain production in antibody-producing cells is either independent of any sequences enhancing transcription or else these can easily be replaced by other DNA sequences with a similar function that have been moved into the vicinity of the V region.
免疫球蛋白（Ig）基因启动子仅在B淋巴细胞谱系的细胞中具有活性。转染实验表明，这部分归因于组织特异性的“激活”DNA序列，即所谓的增强子。目前尚不完全清楚这些序列对于基因的初始激活是否必要，还是对于基因转录的维持也同样必要。我们在此描述了一种小鼠杂交瘤细胞系的分离和特性鉴定，该细胞系在体外已从其唯一包含的活性IgH基因座中删除了“激活”序列。然而，变异细胞的Ig重链产生并未受损，并且与其他杂交瘤细胞相当。因此，抗体产生细胞中Ig重链的高产量要么独立于任何增强转录的序列，要么这些序列可以很容易地被具有类似功能且已转移到V区附近的其他DNA序列所取代。
