Abstract
It has recently become clear that recombination of Ig genes is not restricted to B cell precursors but that secondary rearrangements can also occur under certain conditions in phenotypically immature bone marrow and peripheral B cells. However, the nature of these cells and the regulation of secondary V(D)J recombination in response to B cell receptor (BCR) stimulation remain controversial. In the present study, we have analyzed secondary light chain gene rearrangements and recombination activating gene (RAG) expression in the surface IgM+, IgD- murine B cell line, 38C-13, which has previously been found to undergo kappa light chain replacement. We find that 38C-13 cells undergo spontaneous secondary Vkappa-Jkappa and RS rearrangements in culture, with recombination occurring on both productive and nonproductive alleles. Both 38C-13 cells and the Id-negative variants express the RAG genes, indicating that the presence of RAG does not depend on activation via the 38C-13 BCR. Moreover, BCR cross-linking in 38C-13 cells leads to a rapid and reversible down-regulation of RAG2 mRNA. Therefore, 38C-13 cells resemble peripheral IgM+, IgD- B cells undergoing light chain gene rearrangement and provide a possible in vitro model for studying peripheral V(D)J recombination.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Animals
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Antibody Diversity / genetics
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B-Lymphocytes / immunology
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B-Lymphocytes / metabolism*
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Cell Line
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DNA-Binding Proteins / antagonists & inhibitors
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DNA-Binding Proteins / biosynthesis
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DNA-Binding Proteins / genetics*
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Down-Regulation / genetics
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Down-Regulation / immunology*
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Gene Expression Regulation / immunology*
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Gene Rearrangement, B-Lymphocyte, Light Chain*
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Genetic Variation / immunology
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Immunoglobulin Idiotypes / chemistry
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Immunoglobulin Idiotypes / genetics
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Immunoglobulin Idiotypes / isolation & purification
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Immunoglobulin Joining Region / biosynthesis
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Immunoglobulin Joining Region / genetics*
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Immunoglobulin Variable Region / biosynthesis
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Immunoglobulin Variable Region / genetics*
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Immunoglobulin kappa-Chains / biosynthesis
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Immunoglobulin kappa-Chains / genetics
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Mice
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Receptors, Antigen, B-Cell / immunology
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Receptors, Antigen, B-Cell / metabolism
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Receptors, Antigen, B-Cell / physiology*
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Transcription, Genetic / immunology
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Transposases / genetics
Substances
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DNA-Binding Proteins
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Immunoglobulin Idiotypes
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Immunoglobulin Joining Region
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Immunoglobulin Variable Region
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Immunoglobulin kappa-Chains
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Rag2 protein, mouse
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Receptors, Antigen, B-Cell
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V(D)J recombination activating protein 2
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Transposases