Zezza D J, Mikoryak C A, Schwager J, Steiner L A
Department of Biology, Massachusetts Institute of Technology, Cambridge 02139.
J Immunol. 1991 Jun 1;146(11):4041-7.
A cDNA expression library, prepared from Xenopus laevis splenocytes, was screened with antibodies to Xenopus Ig. One clone, lambda XIg23, reacted with antibodies to IgY and to IgM; the insert hybridized to approximately 1.3-kb RNA from spleen, the approximate size expected for L chain mRNA. An additional clone, lambda XIg31, was identified by cross-hybridization. The inserts of lambda XIg23 and lambda XIg31 begin in the third framework region of the V region and extend through the C region to the poly(A) tail. Except for a single nucleotide difference, the two C region sequences are identical. The amino acid sequence of the C region was compared with the sequences of a variety of C kappa and C lambda, as well as to C region sequences of L chains from Rana catesbeiana and from two species of shark. The Xenopus C region resembles mouse and human C kappa slightly more than C lambda. The similarity of the Xenopus and Rana C regions to each other is approximately the same as that of either amphibian sequence to mammalian CL. The data are discussed in terms of the evolution of kappa and lambda C regions.
用针对非洲爪蟾免疫球蛋白（Ig）的抗体筛选了一个由非洲爪蟾脾细胞制备的cDNA表达文库。一个克隆，λXIg23，与针对IgY和IgM的抗体发生反应；其插入片段与来自脾脏的约1.3kb RNA杂交，这是轻链mRNA预期的大致大小。通过交叉杂交鉴定出另一个克隆λXIg31。λXIg23和λXIg31的插入片段从V区的第三个框架区开始，延伸穿过C区直至poly(A)尾。除了一个单核苷酸差异外，两个C区序列相同。将C区的氨基酸序列与多种Cκ和Cλ的序列进行了比较，还与牛蛙以及两种鲨鱼的轻链C区序列进行了比较。非洲爪蟾的C区与小鼠和人类的Cκ的相似性略高于Cλ。非洲爪蟾和牛蛙C区之间的相似性与任一两栖动物序列与哺乳动物CL的相似性大致相同。根据κ和λ C区的进化对这些数据进行了讨论。
