Accessibility of the promoter sequence in the J-chain gene is regulated by chromatin changes during B-cell differentiation.
The gene for the immunoglobulin M (IgM)-polymerizing protein, the J chain, is activated when the mature B cell is triggered to secrete pentamer IgM. Activation of the gene was found to be associated with chromatin changes in a 240-base-pair region at the 5' end of the gene. Analyses of lymphoid lines showed that the 5' region was resistant to nuclease digestion at the immature B-cell stage; it became slightly more accessible in mature B cells and cells at an early stage in the IgM response and then displayed an open, hypersensitive structure in IgM-secreting cells. In addition, analyses of normal, mitogen-stimulated lymphocytes showed that the open hypersensitive structure was coinducible with J-chain gene expression. These results suggest that the 5' chromatin changes precede transcription, making control sequences within the site accessible to regulatory factors.
D001402:B-Lymphocytes / Q000166:cytology / Q000276:immunology*; D002454:Cell Differentiation; D002460:Cell Line; D002478:Cells, Cultured; D002843:Chromatin / Q000378:metabolism*; D004262:DNA Restriction Enzymes; D005796:Genes; D006801:Humans; D007144:Immunoglobulin J-Chains / Q000235:genetics*; D008223:Lymphoma / Q000276:immunology; D011401:Promoter Regions, Genetic
D002843:Chromatin; D007144:Immunoglobulin J-Chains; D004262:DNA Restriction Enzymes