tokens: Gel-retardation experiments show that Spi-B can bind to all putative PU . 1 binding sites , but do not reveal any preferred Spi-B binding site .
folded_tokens: gel-retardation experiments show that spi-b can bind to all putative pu . 1 binding sites , but do not reveal any preferred spi-b binding site .
labels: B-other_name I-other_name O O B-protein_molecule O O O O B-DNA_domain_or_region B-protein_molecule I-protein_molecule I-protein_molecule O O O O O O O O O B-protein_molecule O O O