The interaction of rat uterine cytosol oestrogen-receptor complexes with the synthetic acceptor oligo(dT)-cellulose was studied. Differences in the stability of receptor complexes and their ability to bind to oligo(dT)-cellulose on storage at 4 degrees C or when exposed to increased temperatures indicated heterogeneity of steroid- and oligonucleotide-binding sites. Dilution, dialysis and (NH4)2SO4 precipitation increased the interaction of receptor complexes with oligo(dT)-cellulose (a step termed activation). This increase may be the result of the removal of low-molecular-weight cytosol components which inhibit receptor activation, dimerization to the 5 S form, which binds to oligo(dT)-cellulose, or interaction of 5 S receptor with the oligonucleotide. Cytosol oestradiol-receptor complexes exhibited biphasic dissociation kinetics. All these manipulations resulted in an increase in the proportion of the slow-dissociating component equivalent to the increase in receptor binding to oligo(dT)-cellulose. In contrast, addition of 10mM-sodium molybdate to cytosol decreased both oligo(dT)-cellulose binding and the proportion of receptor with slow dissociation kinetics. The inclusion of proteinase inhibitors did not affect interactions of receptor with oligo(dT)-cellulose nor the dissociation kinetics. These results suggest that oligo(dT)-cellulose binding may serve to quantify the proportion of cytosol receptor in an active form capable of nuclear interaction and to help to ascertain whether a receptor system is fully functional. This binding procedure could prove useful in the evaluation of oestrogen responsivity under normal and pathological conditions.
The binding of rat uterine cytosol oestrogen receptors to oligodeoxythymidylate-cellulose. Its relationship to a stable form of receptor complex with separate ligand- and oligonucleotide-binding sites
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L Myatt, M G Elder, C Neethling, L Lim; The binding of rat uterine cytosol oestrogen receptors to oligodeoxythymidylate-cellulose. Its relationship to a stable form of receptor complex with separate ligand- and oligonucleotide-binding sites. Biochem J 15 January 1982; 202 (1): 203–209. doi: https://doi.org/10.1042/bj2020203
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