tokens: Primer extension and nuclease S1 protection analysis revealed two major transcription initiation sites .
folded_tokens: primer extension and nuclease s1 protection analysis revealed two major transcription initiation sites .
labels: B-other_name I-other_name O B-other_name I-other_name I-other_name I-other_name O O O B-DNA_domain_or_region I-DNA_domain_or_region I-DNA_domain_or_region O