Selective binding of mouse estradiol.receptor complexes to oligo(dT)-cellulose.

As a model for the nonspecific interaction of steroid receptors with DNA, the binding of estradiol.receptor complexes of mouse kidney and uterine cytosols to oligo(dT)-cellulose was studied in detail. A limited concentration range of monovalent cationic salts was required for optimal binding, regardless of prior activation of the receptor complexes or the oligomer ligand. Thermal activation of the receptor complexes did not facilitate binding. The reaction was selective for intracellular steroid hormone.receptor complexes, as extracellular proteins binding estradiol with low affinity (bovine serum albumin) or high affinity (mouse alpha-fetoprotein) were inactive. Both crude and partially purified kidney cytosol receptor complexes bound preferentially to oligo(dT)- and oligo(dC)-celluloses, rather than oligo(dA)-celluloses. These findings suggest that at least part of the nonspecific interaction of estradiol.receptor complexes with native DNA is through a salt-sensitive binding of the complex to pyrimidine-rich surfaces of the DNA.