EFFECT OF 1,10-PHENANTHROLINE ON DNA-BINDING BY 1,25-(OH)(2) VITAMIN-D-RECEPTOR

The effect of the chelator 1,10-phenanthroline on the DNA-binding of 1 ,25-dihydroxyvitamin D receptor was demonstrated. Increasing concentra tions of the chelator, up to 3 mM, decreased receptor binding to DNA-c ellulose. This effect was specific for the chelating function because the nonchelating analog, 1,7-phenanthroline, did not inhibit DNA-cellu lose binding of the receptor. The cations Cd2+ and Zn2+ were able to b lock chelator-mediated inhibition. These cations were unable to revers e the inhibition unless 1,10-phenanthroline was removed by dialysis.