tokens: Two different proteins which independently bound to neighboring sequences within the negative regulatory element ( NRE ) of human immunodeficiency virus type 1 ( HIV-1 ) were detected in the nuclear extract of a virus-infected human T cell line .
folded_tokens: two different proteins which independently bound to neighboring sequences within the negative regulatory element ( nre ) of human immunodeficiency virus type 1 ( hiv-1 ) were detected in the nuclear extract of a virus-infected human t cell line .
labels: O O O O O O O B-other_name I-other_name O O B-DNA_domain_or_region I-DNA_domain_or_region I-DNA_domain_or_region O B-DNA_domain_or_region O O B-virus I-virus I-virus I-virus I-virus O B-virus O O O O O O O O O B-cell_line I-cell_line I-cell_line I-cell_line I-cell_line O