Structural analysis of a rabbit immunoglobulin kappa 2 J-C locus reveals multiple deletions.
We previously reported that domestic rabbits harbor at least two DNA sequences that hybridize strongly to immunoglobulin kappa C region probes in Southern blots. One of these was cloned from a domestic b4 rabbit and identified as the gene for the nominal b4 allotype kappa chain which is expressed at high levels. We now have cloned (from a b4 rabbit) the other homologous sequence and find that it encodes a kappa chain nearly identical to the kappa 2 chain of "bas" rabbits, which is not normally expressed at detectable levels in domestic rabbits. Sequence analysis of this kappa 2 chain reveals a J kappa -C kappa locus with no obvious coding sequence defects that could explain its low expression. However, several base changes in a putative enhancer region as well as deletions (totalling about 1.5 kb) in the J-C intron might be related to low expression. The comparison between these two kappa genes raises questions about the selective pressures operating during the evolution of this gene system.
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D002872:Chromosome Deletion; D003001:Cloning, Molecular; D004262:DNA Restriction Enzymes; D005796:Genes; D007127:Immunoglobulin Constant Regions / Q000235:genetics*; D007144:Immunoglobulin J-Chains / Q000235:genetics*; D007147:Immunoglobulin Light Chains / Q000235:genetics*; D007145:Immunoglobulin kappa-Chains / Q000235:genetics*; D007136:Immunoglobulins / Q000235:genetics*; D009693:Nucleic Acid Hybridization; D011817:Rabbits
D007127:Immunoglobulin Constant Regions; D007144:Immunoglobulin J-Chains; D007147:Immunoglobulin Light Chains; D007145:Immunoglobulin kappa-Chains; D007136:Immunoglobulins; D004262:DNA Restriction Enzymes