Immunoglobulin allotypes of rabbit kappa chains: polymorphism of a control mechanism regulating closely linked duplicated genes?

The amino acid sequence of the constant (CK) region from the kappa immunoglobulin chains of a b9 rabbit is compared with the CK sequences, taken from the literature, of a b4 rabbit. These CK regions differ by 33% of their amino acid sequences and by three sequence insertions or deletions (sequence gaps). These extensive differences together with other published observations suggest that the b9 and b4 CK genes may not be simple alleles, but rather they may be encoded by closely linked CK genes present in every rabbit whose expression is regulated by a polymorphic control mechanism

Silkmoth chorion proteins: sequence analysis of the products of a multigene family.

Five polypeptide components have been isolated from the eggshell (chorions) of a silkmoth. Two are homogeneous on sodium dodecyl sulfate and isoelectric focusing gels, and three contain predominantly two proteins each. Amino acid analyses show that all five components are similar to each other. These proteins have been sequenced from the amino terminus. Homogeneous components yielded single sequences; heterogeneous components yielded two residues at some positions, consistent with their containing two major electrophoretic components. Striking similarities are apparent among all these sequences. These similarities can be increased dramatically by separating each of the three protein mixtures into two sequences and introducing a small number of gaps or insertions. This is due in part to bringing into register a portion that contains short repeating subunits found in all sequences. All proteins are also characterized by a region of high cysteine content near the amino terminus followed by a longer low-cysteine region. The data suggest that these proteins share a common evolutionary origin and are encoded by a multigene family

The structural correlates of the rabbit light chain b allotypes: Sequence studies of b5 and b6 chains

Rabbit kappa light chains of allotype b5 and b6 were prepared from antibodies of restricted heterogeneity made by animals hyperimmunized with, respectively, strain III and strain II pneumococcal vaccines. The amino-acid sequence of several tryptic peptides were determined. The variable region fragments of the b5 and b6 chains appear to be quite similar to the corresponding fragments of b4 and b9 chains, albeit some residues seem to be allotype associated. In contrast the chains of different allotypes vary right from the start of the constant region in a number of positions, suggesting that b allotypes correlate with amino-acid substitutions in this region. The number of substitutions between the b5 and b6 and the previously determined b4 and b9 constant regions sequences ranges from 20 to 35%. Serological studies suggest that Leporidae b allotypes diverged no more than 2 × 106 years ago. By this time only 1% of the substitutions could be generated by 'conventional evolution'. Duplication and mutation of the individual CK genes could account for the high level of divergence observed. The data reported here support the notion that the structural genes encoding the light chain constant regions of the various b allotypes coexist on the same chromosome and that the allelism is controlled by a regulatory mechanism. © 1979.SCOPUS: ar.jinfo:eu-repo/semantics/publishe