Dynamic Chromatin Remodeling in the Vicinity of J Chain Gene for the Regulation of Two Stage-specific Genes during B Cell Differentiation

Dynamic chromatin remodeling during B cell differentiation was identified in the vicinity of J chain gene. In pre-B cells, the enhancer-containing DNase I hypersensitive sites (HSSs) 3–4 were open. However, these HSSs 3–4 turned out to be unassociated with J chain gene expression, as the J chain promoter-containing HSS1 remained in a closed state. The open enhancer HSSs 3–4 in the pre-B cells might be related to the expression of a pre-B cell-specific gene upstream of the HSSs 3–4, which was identified in our Northern blot analyses. The HSSs 3–4 are then closed in the next immature and mature B cell stages until the IL-2 opens the HSSs 3–4 again as well as HSS1 to express J chain gene in the primary immune responses. The dynamic regulation of chromatin structure during B cell differentiation for the expression of two stage-specific genes will provide a good model system for the study of B cell differentiation and gene expression.