In view of these results, it is now of interest to define the position of nucleosomes in hepatocytes with the vitellogenin B1 promoter embedded in its natural context, to determine whether the mechanism of vitellogenin gene B1 induction relies on the interaction of the ER with members of the CTF NFI family, or with those of the C EBP and HNF3 families nolvadex xt Inducible RapGEF2 deletion leads to defective fetal liver erythropoiesis