BINDING OF THE ESTRADIOL-RECEPTOR COMPLEX TO RECONSTITUTED NUCLEOACIDIC PROTEIN FROM CALF UTERUS

Non-histone protein-DNA complexes with acceptor activity for estradiol-receptor complexes were reconstituted from fractionated calf uterine chromatin. Acceptor activity had tissue specificity with target tissue binding exceeding non-target tissue binding. The binding of estradiol-receptor complexes to acceptor sites was dependent on intact non-histone protein-DNA complexes, reconstituted select non-histone proteins and protein equivalent:DNA reconstitution ratios. [3H]Estradiol-receptor complexes were bound to reconstituted non-histone protein-DNA complexes (i.e, nucleoacidic protein) with a high affinity and with a limited number of binding sites. Fractionation of uterine chromatin non-histone proteins identified 2 major sets of non-histone proteins which had acceptor activity when reconstituted with DNA. It seems possible to reconstitute nucleoacidic protein fractions with specific acceptor activity for the calf uterine estrogen receptor.