title: Somatic DNA rearrangement generates functional rat immunoglobulin kappa chain genes: the J kappa gene cluster is longer in rat than in mouse.
abstract: The kappa immunoglobulin (Ig) genes from rat kidney and from rat myeloma cells were cloned and analyzed. In kidney DNA one C kappa species is observed by Southern blotting and cloning in phage vectors; this gene most likely represents the embryonic configuration. In the IR52 myeloma DNA two C kappa species are observed: one in the same configuration seen in kidney and one which has undergone a rearrangement. This somatic rearrangement has brought the expressed V region to within 2.7 kb 5' of the C kappa coding region; the rearrangement site is within the J kappa cluster which we have mapped. The rat somatic Ig rearrangement, therefore, closely resembles that seen in mouse Ig genes. In the rat embryonic fragment two J kappa segments were mapped at 2 and 4.3 kb 5' from the C kappa coding region. Therefore, the rat J kappa cluster extends over about 2.3 kb, a region much longer than the 1.4 kb of the mouse and human J kappa clusters. In the region between C kappa and the expressed J kappa of IR52 myeloma DNA, and XbaI site present in the embryonic kappa gene has been lost. A somatic mutation has therefore occurred in the intervening sequence DNA approx. 0.7 kb 3' from the V/J recombination site. Southern blots of rat kidney DNA hybridized with different rat V kappa probes showed non-overlapping sets of bands which correspond to different subgroups, each composed of 8-10 closely related V kappa genes.
mesh_terms: D000818:Animals; D001483:Base Sequence; D002460:Cell Line; D003001:Cloning, Molecular; D004262:DNA Restriction Enzymes; D004274:DNA, Recombinant / Q000276:immunology; D005796:Genes; D007144:Immunoglobulin J-Chains / Q000235:genetics*; D007147:Immunoglobulin Light Chains / Q000235:genetics*; D007145:Immunoglobulin kappa-Chains / Q000235:genetics*; D007668:Kidney / Q000276:immunology*; D009154:Mutation; D009374:Neoplasms, Experimental / Q000276:immunology; D009693:Nucleic Acid Hybridization; D010954:Plasmacytoma / Q000276:immunology*; D051381:Rats
chemical_list: D004274:DNA, Recombinant; D007144:Immunoglobulin J-Chains; D007147:Immunoglobulin Light Chains; D007145:Immunoglobulin kappa-Chains; D004262:DNA Restriction Enzymes