Chi, a promoter of generalized recombination in λ phage, is present in immunoglobulin genes
Chi, a promoter of generalized recombination in λ phage, is present in immunoglobulin genes
复制标题
Chi 是 λ 噬菌体中广义重组的启动子，存在于免疫球蛋白基因中
作者：
A. Kenter;B. Birshtein
广义重组是一种依赖于同源DNA识别的现象，可能是产生小鼠γ2b-γ2a杂合免疫球蛋白重链的原因1。遗传元件Chi已显示增强原核生物中的广义重组2 -10。序列比较预测Chi存在于小鼠γ2b基因的CH 3结构域中，并且在适当的选择条件下使用噬斑大小作为Chi活性的量度2，3，显示含有γ2b基因的克隆11赋予携带它的γ载体Chi活性。因此，如果Chi在真核系统中有功能，可能促进了产生γ2b-γ2a杂合免疫球蛋白的重组事件。我们在这里报告，在小鼠基因组中的Chi的频率是类似于其他真核生物的独特序列，但低于免疫球蛋白。Chi在免疫球蛋白基因中出现的位置以及从小鼠骨髓瘤细胞系MPC 11中分离的γ2b-γ2a杂合变体可能代表异常类别转换的事实表明，同源重组可能广泛适用于重链类别转换。
Generalized recombination is a phenomenon dependent on recognition of homologous DNA and may be responsible for generating a mouse γ2b–γ2a hybrid immunoglobulin heavy chain1. The genetic element, Chi, has been shown to enhance generalized recombination in prokaryotes2–10. Sequence comparison predicted Chi to be present in the CH3 domain of the mouse γ2b gene, and using plaque size in the appropriate selective conditions as a measure of Chi activity2,3, a clone containing the γ2b gene11 was shown to confer Chi activity on the γ vector which carried it. Thus Chi, if functional in eukaryotic systems, could have promoted the recombinational event which produced the γ2b–γ2a hybrid immunoglobulin. We report here that the frequency of Chi in the mouse genome is similar to that in other eukaryotic unique sequences but lower than in immunoglobulingenes. The positions at which Chi occurs in immunoglobulin genes and the fact that the γ2b–γ2a hybrid variants isolated from mouse myeloma cell line MPC11 may represent an aberrant class switch suggest that homologous recombination may be broadly applicable to the heavy-chain class switch.
突变的聚集使 Chi 重组热点失活。
影响因子：
5.6
作者：
Schultz,DW;Swindle,J;Smith,GR
通讯作者：
Smith,GR