tokens: By using a nucleosome -assembly system derived from Drosophila embryos , we find that the packaging of DNA into chromatin in vitro strongly represses HIV-1 transcription and that repression can be counteracted efficiently by preincubation of the DNA with LEF-1 ( or LEF-1 and Ets-1 ) supplemented with fractions containing the promoter-binding protein , Sp1 .
folded_tokens: by using a nucleosome -assembly system derived from drosophila embryos , we find that the packaging of dna into chromatin in vitro strongly represses hiv-1 transcription and that repression can be counteracted efficiently by preincubation of the dna with lef-1 ( or lef-1 and ets-1 ) supplemented with fractions containing the promoter-binding protein , sp1 .
labels: O O O B-protein_complex O O O O B-multi_cell I-multi_cell O O O O O O O O O B-DNA_family_or_group O O O O B-virus O O O O O O O O O O O O O O B-protein_molecule O O B-protein_molecule O B-protein_molecule O O O O O O B-protein_family_or_group I-protein_family_or_group O B-protein_molecule O