tokens: Studies were initiated with a fragment extending 2 , 738 nucleotides 5' to the transcription start site and lead to the identification of 253 nucleotides retaining full promoter activity in human erythroleukemia cells .
folded_tokens: studies were initiated with a fragment extending 2 , 738 nucleotides 5' to the transcription start site and lead to the identification of 253 nucleotides retaining full promoter activity in human erythroleukemia cells .
labels: O O O O O O O B-polynucleotide I-polynucleotide I-polynucleotide I-polynucleotide O O O B-DNA_domain_or_region I-DNA_domain_or_region I-DNA_domain_or_region O O O O O O B-polynucleotide I-polynucleotide O O B-other_name I-other_name O B-cell_type I-cell_type I-cell_type O