Emorine L, Max E E
Nucleic Acids Res. 1983 Dec 20;11(24):8877-90. doi: 10.1093/nar/11.24.8877.
We previously reported that domestic rabbits harbor at least two DNA sequences that hybridize strongly to immunoglobulin kappa C region probes in Southern blots. One of these was cloned from a domestic b4 rabbit and identified as the gene for the nominal b4 allotype kappa chain which is expressed at high levels. We now have cloned (from a b4 rabbit) the other homologous sequence and find that it encodes a kappa chain nearly identical to the kappa 2 chain of "bas" rabbits, which is not normally expressed at detectable levels in domestic rabbits. Sequence analysis of this kappa 2 chain reveals a J kappa -C kappa locus with no obvious coding sequence defects that could explain its low expression. However, several base changes in a putative enhancer region as well as deletions (totalling about 1.5 kb) in the J-C intron might be related to low expression. The comparison between these two kappa genes raises questions about the selective pressures operating during the evolution of this gene system.
我们先前报道，家兔在Southern印迹中含有至少两个与免疫球蛋白κC区探针强烈杂交的DNA序列。其中一个是从一只家兔b4中克隆出来的，被鉴定为命名为b4同种异型κ链的基因，该基因高水平表达。我们现在（从一只b4兔中）克隆了另一个同源序列，发现它编码的κ链与“bas”兔的κ2链几乎相同，在家兔中该链通常不以可检测水平表达。对该κ2链的序列分析揭示了一个Jκ-Cκ基因座，没有明显的编码序列缺陷可以解释其低表达。然而，一个假定增强子区域的几个碱基变化以及J-C内含子中的缺失（总计约1.5 kb）可能与低表达有关。这两个κ基因之间的比较引发了关于该基因系统进化过程中作用的选择压力的问题。
