tokens: In the erythroleukemia cell line K562 , due to the absence of Spi-B , only PU . 1 bound to the Btk promoter .
folded_tokens: in the erythroleukemia cell line k562 , due to the absence of spi-b , only pu . 1 bound to the btk promoter .
labels: O O B-cell_line I-cell_line I-cell_line I-cell_line O O O O O O B-protein_molecule O O B-protein_molecule I-protein_molecule I-protein_molecule O O O B-protein_molecule O O