IG GENETICS--ONTOGENY AND DIFFERENTIATION OF CELLS OF THE RABBIT IMMUNE SYSTEM

我们使用经典的免疫遗传学和分子生物学技术 研究兔免疫球蛋白（Ig）和T细胞的遗传学 受体（Tcr），并研究IG和 淋巴细胞发育过程中的Tcr基因。 我们报告了第十三次实验室观察到的VH-CH 重组（R2 M）。所有13个重组都有 发生在父本身上。 R2 M重组位点定位于 VH基因和JH基因的5 '端，如先前三个位点所做的那样， 特征重组。 R2 M位点定位于D1 d DH基因的3 '端 其朝向含DH区域的3 '端，并且可能在 或接近重复DNA的片段。 可以有两个或更多 重复DNA片段内或附近的“重组热点” 在兔子的含DH区域。 我们获得了DBeta 2和JBeta 2的完整基因组序列， 与存在于一些兔子中的嵌合CBeta基因相关的片段。 兔JBeta 2簇有6个功能片段，1个假基因， 以及J β 2.2和J β 2.3之间的另一假基因的残基， 与人体内相同部位的相同。 JBeta2.5 兔的一个基因片段失去了剪接信号，为假基因 与人和老鼠的对应物不同。 总组织 所有三个物种的DBeta 2-JBeta 2区域中的基因片段是 在DNA序列的长延伸上显着保守; 与人的相似性高于小鼠。 在美国国立卫生研究院饲养的兔子， 缺乏C21且仅表达C7的链。 这些兔子被证明 产生具有与产物对应的序列的mRNA和蛋白质 先前鉴定的基因组λ轻链基因，CxD 6。 已知c2 l的产生是由于C21 - 5的表达。 的 c2 l-阴性表型反映了包括Jc 21 da 5的区域的缺失。 c7阴性表型似乎也是由缺失引起的。

We use techniques of classical immunogenetics and of molecular biology to study the genetics of rabbit immunoglobulins (Igs) and T cell receptors (Tcr) and to investigate the regulated expression of Ig and Tcr genes during lymphoid cell development. We reported the thirteenth laboratory observation of a VH-CH recombination (R2M) in the rabbit. All thirteen recombinations have occurred in the male parent. The R2M recombination site maps 3'of the VH genes and 5'of the JH genes as did the sites of three previously characterized recombinations. The R2M site maps 3'of the D1d DH gene which is toward the 3'end of the DH-containing region and is probably in or near stretches of repetitive DNA. There may be two or more "hot-spots of recombination" within or near stretches of repetitive DNA in the DH-containing region of the rabbit. We obtained the complete genomic sequences of the DBeta2 and JBeta2 segments associated with a chimeric CBeta gene present in some rabbits. The rabbit JBeta2 cluster has six functional segments, one pseudogene, and a remnant of another pseudogene between JBeta2.2 and JBeta2.3, equivalent to the one found in man at the same location. The JBeta2.5 gene segment of rabbit has lost the splice signal and is a pseudogene unlike its counterparts in man and mouse. The general organization of the gene segments in the DBeta2-JBeta2 regions of all three species is remarkably conserved over long stretches of DNA sequence; there is higher similarity to human than mouse. Rabbits were bred at the NIH to produce elevated levels of lambda light chains lacking c2l and expressing only c7. These rabbits were shown to produce mRNA and proteins with sequences corresponding to the products of a previously identified genomic lambda light chain gene, Clambda6. The production of c2l is known to be due to expression of Clambda5. The c2l-negative phenotype reflects deletion of a region including Jlambda5. Tbe c7-negative phenotype also appears to result from a deletion.