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 i n the vicinity of J chain gene. In pre-B cells, the enhancer-containing DNa se I hypersensitive sites (HSSs) 3-4 were open. However, these HSSs 3-4 tur ned out to be unassociated with J chain gene expression, as the J chain pro moter-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-spe cific gene upstream of the HSSs 3-4, which was identified in our Northern b lot 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 ex press 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.