tokens: Positive regulatory element I ( PRE-I ) is a strong enhancer element essential for expression of the human IL-4 gene .
folded_tokens: positive regulatory element i ( pre-i ) is a strong enhancer element essential for expression of the human il-4 gene .
labels: B-DNA_domain_or_region I-DNA_domain_or_region I-DNA_domain_or_region I-DNA_domain_or_region O B-DNA_domain_or_region O O O O B-DNA_domain_or_region I-DNA_domain_or_region O O O O O B-DNA_domain_or_region I-DNA_domain_or_region I-DNA_domain_or_region O