Locus control regions ( LCRs ) are powerful assemblies of cis elements that organize the actions of cell-type-specific trans-acting factors .
locus control regions ( lcrs ) are powerful assemblies of cis elements that organize the actions of cell-type-specific trans-acting factors .
B-DNA_domain_or_region I-DNA_domain_or_region I-DNA_domain_or_region O B-DNA_domain_or_region O O O O O B-DNA_family_or_group I-DNA_family_or_group O O O O O B-protein_family_or_group I-protein_family_or_group I-protein_family_or_group O