title: Targeted disruption of mu chain membrane exon causes loss of heavy-chain allelic exclusion.
abstract: Burnet's clonal selection theory suggests that each B lymphocyte is committed to a single antibody specificity. This is achieved by a programme of somatic rearrangements of the gene segments encoding antibody variable (V) regions, in the course of B-cell development. Evidence from immunoglobulin-transgenic mice and immunoglobulin-gene-transfected transformed pre-B cells suggest that the membrane form of the immunoglobulin heavy (H) chain of class mu (microns), expressed from a rearranged H-chain (IgH) locus, may signal allelic exclusion of the homologous IgH locus in the cell and initiation of light (L)-chain gene rearrangement in the Ig kappa loci. We report here that targeted disruption of the membrane exon of the mu chain indeed results in the loss of H-chain allelic exclusion. But, some kappa chain gene rearrangement is still observed in the absence of micron expression.
authors.affiliation: Institute for Genetics, University of Cologne, Germany.
authors.forename: D
authors.initials: D
authors.lastname: Kitamura
authors.forename: K
authors.initials: K
authors.lastname: Rajewsky
mesh_terms: D000483:Alleles; D000818:Animals; D001402:B-Lymphocytes / Q000276:immunology*; D001483:Base Sequence; D001854:Bone Marrow Cells; D004247:DNA / Q000737:chemistry; D005091:Exons; D015326:Gene Rearrangement, B-Lymphocyte, Heavy Chain; D015328:Gene Rearrangement, B-Lymphocyte, Light Chain; D005803:Genes, Immunoglobulin; D007145:Immunoglobulin kappa-Chains / Q000235:genetics; D007148:Immunoglobulin mu-Chains / Q000235:genetics*; D051379:Mice; D008807:Mice, Inbred BALB C; D008810:Mice, Inbred C57BL; D008822:Mice, Transgenic; D008969:Molecular Sequence Data; D009154:Mutation; D016133:Polymerase Chain Reaction; D013154:Spleen / Q000166:cytology
chemical_list: D007145:Immunoglobulin kappa-Chains; D007148:Immunoglobulin mu-Chains; D004247:DNA