Positive and negative regulation of immunoglobulin gene expression by a novel B-cell-specific enhancer element .
positive and negative regulation of immunoglobulin gene expression by a novel b-cell-specific enhancer element .
O O O O O B-DNA_family_or_group I-DNA_family_or_group O O O O B-DNA_domain_or_region I-DNA_domain_or_region I-DNA_domain_or_region O