Multiple sequences related to a constant-region kappa light chain gene in the rabbit genome

Abstract

Four allelic genes control kappa light chain allotypes in the rabbit. Amino acid sequence studies have revealed an extensive divergence (22%–33%) in the alternative forms of the kappa constant region (b4, b5, b6 and bg). Furthermore, independent studies have shown that a rabbit could express a wrong allotype. To assess the hypothesis that b allotypes are encoded by duplicated genes with a polymorphic control mechanism, we have analyzed the DNAs of four different homozygous rabbits using the Southern blot hybridization technique, with a cloned b4 C κ probe. DNAs of individual b4, b5, b6 and b9 rabbits were cleaved with Eco RI, Kpn I and Pst I restriction endonucleases. Comparative analysis of restriction patterns shows that all four rabbit DNAs contain multiple DNA fragments hybridizing with the probe under low- and high-stringency washing conditions. In addition, each restriction pattern is distinct, suggesting that the C κ genes are organized differently in animals expressing different allotypes.