Wang X F, Calame K
Cell. 1985 Dec;43(3 Pt 2):659-65. doi: 10.1016/0092-8674(85)90238-7.
The availability of a clone containing two linked immunoglobulin heavy chain variable region genes located 15.8 kb apart has allowed us to study the functional capabilities of the immunoglobulin heavy chain transcriptional enhancer element in its normal chromosomal context. In plasmacytoma J606 the 3' VH gene is joined to D and J gene segments, located within 1.7 kb of the heavy chain enhancer, and expressed; the 5' VH gene is 17.5 kb from the enhancer in J606 DNA. Run-on transcription in isolated nuclei demonstrated specific transcription of the 5' VH gene in J606 that was 60% that of the expressed 3' VH gene. No other enhancer elements are detectable closer to the 5' VH gene than the known heavy chain enhancer. Thus, the heavy chain enhancer appears to be capable of activating transcription of a VH promoter located 17.5 kb away and of activating two tandem VH promoters.
含有两个相距15.8 kb的连锁免疫球蛋白重链可变区基因的克隆的获得，使我们能够在其正常染色体背景下研究免疫球蛋白重链转录增强子元件的功能。在浆细胞瘤J606中，3' VH基因与位于重链增强子1.7 kb范围内的D和J基因片段连接并表达；在J606 DNA中，5' VH基因距增强子17.5 kb。分离细胞核中的连续转录显示，J606中5' VH基因的特异性转录为表达的3' VH基因的60%。在比已知重链增强子更靠近5' VH基因的位置，未检测到其他增强子元件。因此，重链增强子似乎能够激活位于17.5 kb以外的VH启动子的转录，并激活两个串联的VH启动子。
