title: Light chain replacement: a new model for antibody gene rearrangement.
abstract: A functional B cell antigen receptor is thought to regulate antibody gene rearrangement either by stopping further rearrangement (exclusion) or by promoting additional rearrangement (editing). We have developed a new model to study the regulation of antibody gene rearrangement. In this model, we used gene targeting to replace the J kappa region with a functional V kappa-J kappa light chain gene. Two different strains of mice were created; one, V kappa 4R, has a V kappa 4-J kappa 4 rearrangement followed by a downstream J kappa 5 segment, while the other, V kappa 8R, has a V kappa 8-J kappa 5 light chain. Here, we analyze the influence of these functional light chains on light chain rearrangement. We show that some V kappa 4R and V kappa 8R B cells only have the V kappa R light chain rearrangement, whereas others undergo additional rearrangements. Additional rearrangement can occur not only at the other kappa allele or isotype (lambda), but also at the targeted locus in both V kappa 4R and V kappa 8R. Rearrangement to the downstream J kappa 5 segment is observed in V kappa 4R, as is deletion of the targeted locus in both V kappa 4R and V kappa 8R. The V kappa R models illustrate that a productively rearranged light chain can either terminate further rearrangement or allow further rearrangement. We attribute the latter to editing of autoantibodies and to corrections of dysfunctional receptors.
authors.affiliation: Department of Molecular Biology, Princeton University, New Jersey 08544, USA.
authors.forename: E L
authors.initials: EL
authors.lastname: Prak
authors.forename: M
authors.initials: M
authors.lastname: Weigert
mesh_terms: D000818:Animals; D001402:B-Lymphocytes / Q000502:physiology*; D001483:Base Sequence; D017931:DNA Primers / Q000737:chemistry; D015328:Gene Rearrangement, B-Lymphocyte, Light Chain; D005803:Genes, Immunoglobulin; D006825:Hybridomas; D007145:Immunoglobulin kappa-Chains / Q000235:genetics*; D051379:Mice; D008969:Molecular Sequence Data; D011995:Recombination, Genetic
chemical_list: D017931:DNA Primers; D007145:Immunoglobulin kappa-Chains