Sulfhydryl-modifying reagents reversibly inhibit binding of glucocorticoid-receptor complexes to DNA-cellulose.
Glucocorticoid -receptor complexes from intact rat thymus cells incubated with [3H]dexamethasone at 0 degree C are in the nonactivated form and do not bind to DNA-cellulose. Upon being warmed, they are transformed to activated complexes that bind to DNA-cellulose at 0 degree C. We have found that treatment of dexamethasone-receptor complexes with the sulfhydryl-modifying reagents methyl methanethiosulfonate ( MMTS ) and 5,5'-dithiobis(2-nitrobenzoic acid) (DTNB), either before or after the warming, inhibits subsequent binding to DNA-cellulose. The effects of these reagents can be reversed at 0 degree C by dithioerythritol and other sulfhydryl-containing compounds. These results provide the first clear evidence that sulfhydryl-modifying reagents inhibit the binding of activated dexamethasone-receptor complexes to DNA-cellulose and suggest that sulfhydryl groups may be located in or near the DNA binding domain of the rat thymus glucocorticoid-receptor complex. Furthermore, addition of dithioerythritol at 0 degree C to nonactivated receptor complexes that have been treated with MMTS or DTNB produces a substantial increase in the capacity of these complexes to bind to DNA-cellulose, raising the possibility that sulfhydryl groups may be associated with a region on the receptor that plays a critical role in the activation process.
D000818:Animals; D004247:DNA / Q000378:metabolism*; D004226:Dithioerythritol / Q000494:pharmacology; D008297:Male; D010084:Oxidation-Reduction; D011485:Protein Binding / Q000187:drug effects; D051381:Rats; D011965:Receptors, Glucocorticoid / Q000187:drug effects* / Q000378:metabolism; D011987:Receptors, Steroid / Q000187:drug effects*; D013439:Sulfhydryl Reagents / Q000494:pharmacology*
D011965:Receptors, Glucocorticoid; D011987:Receptors, Steroid; D013439:Sulfhydryl Reagents; D004226:Dithioerythritol; D004247:DNA