Involvement of a second lymphoid-specific enhancer element in the regulation of immunoglobulin heavy-chain gene expression .
involvement of a second lymphoid-specific enhancer element in the regulation of immunoglobulin heavy-chain gene expression .
O O O O B-DNA_domain_or_region I-DNA_domain_or_region I-DNA_domain_or_region O O O O B-DNA_domain_or_region I-DNA_domain_or_region I-DNA_domain_or_region O O