Picard D, Schaffner W
Nature. 1984;307(5946):80-2. doi: 10.1038/307080a0.
During differentiation of lymphocytes into antibody-producing cells, an immunoglobulin kappa variable-region gene is transcriptionally activated by rearrangement linking it to a kappa constant (C kappa) region gene which is already transcribed prior to somatic rearrangement. The presence of a transcriptional enhancer element within the large intron of the kappa light-chain gene has been postulated to explain this mode of activation, supported by evidence of a chromatin region which is preferentially accessible to DNase I and restriction enzymes. This DNA region contains a segment of about 130 base pairs (bp) which is strongly conserved between mouse, rabbit and man. Moreover, no transcripts are detectable from a kappa gene, which is truncated within the large intron. Recently, a lymphocyte-specific enhancer has been identified downstream of the joining region in immunoglobulin heavy-chain genes. We now show direct evidence for a functionally similar enhancer within the large kappa gene intron of the mouse. It is, however, less active than the heavy-chain gene enhancer. In contrast, no enhancer was found to be associated with a cloned lambda I light-chain gene.
在淋巴细胞分化为抗体产生细胞的过程中，免疫球蛋白κ可变区基因通过重排与κ恒定（Cκ）区基因相连而被转录激活，该Cκ区基因在体细胞重排之前就已被转录。κ轻链基因大内含子中存在转录增强子元件，这一点被认为可以解释这种激活方式，DNase I和限制酶优先作用的染色质区域的证据支持了这一观点。该DNA区域包含一段约130个碱基对（bp）的片段，在小鼠、兔子和人类之间高度保守。此外，在大内含子内被截断的κ基因没有可检测到的转录本。最近，在免疫球蛋白重链基因的连接区下游发现了一种淋巴细胞特异性增强子。我们现在展示了小鼠κ基因大内含子中存在功能类似增强子的直接证据。然而，它的活性低于重链基因增强子。相比之下，未发现与克隆的λI轻链基因相关的增强子。
