EMS analyses utilizing a series of mutated pp repeat elements demonstrate that the nucleotide sequence requirements for U1 ( U1A/U1B ) and U2 formation are separable from those required for C1-C3 formation .
ems analyses utilizing a series of mutated pp repeat elements demonstrate that the nucleotide sequence requirements for u1 ( u1a/u1b ) and u2 formation are separable from those required for c1-c3 formation .
O O O O O O B-DNA_domain_or_region I-DNA_domain_or_region I-DNA_domain_or_region I-DNA_domain_or_region O O O B-other_name I-other_name I-other_name O B-DNA_domain_or_region O B-DNA_domain_or_region O O B-DNA_domain_or_region O O O O O O O B-DNA_domain_or_region O O