The negative-acting sequences repress enhancer activity in a position- and orientation-independent manner at the pre-B-cell stage .
the negative-acting sequences repress enhancer activity in a position- and orientation-independent manner at the pre-b-cell stage .
O B-DNA_domain_or_region I-DNA_domain_or_region B-other_name I-other_name I-other_name O O O O O O O O B-other_name I-other_name O