Protein-DNA interactions in the promoter region of the chicken vitellogenin II gene were analyzed by in vivo dimethylsulphate footprinting with expressing and non-expressing tissues. The reactivity of G-residues is essentially the same in erythrocytes, oviduct and control liver, not expressing the gene. In the expressing estrogen-induced liver we find a number of G-residues with altered reactivities. These G's are located within distinct sequences: the estrogen responsive elements, a sequence resembling the NF-1 recognition motive, and several elements which are conserved between yolk protein genes. The expression-dependent binding of proteins to these sites was confirmed by DNaseI footprinting applied to nuclei isolated from estrogen-induced and control liver. Estradiol appears to establish a transcription complex comprising a number of distinct proteins bound to different sites in the 5' flanking region of the vitellogenin II gene.