Purification of chicken intestinal receptor for 1,25-dihydroxyvitamin D.

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Abstract
The 3.3S chicken intestinal receptor for 1,25-dihydroxyvitamin D [1,25-(OH)2D] was purified approximately 86,000-fold from the cytosolic fraction. The receptor was selectively precipitated with polymin P from high-speed supernatants derived from 800 g of intestinal mucosa and then sequentially chromatographed on DNA-cellulose, Sephacryl, blue dextran-Sepharose, DNA-cellulose and heparin-Sepharose. Polyacrylamide gel electrophoresis of 8-10 .mu.g of the purified receptor in sodium dodecyl sulfate indicated the presence of 1 major and 3 minor protein bands of MW 50,000-65,000. Sucrose gradient analysis of the purified material in 0.3 M KCl suggested that a fraction of the receptor remained complexed to the 1,25-(OH)2D and that its sedimentation property of 3.3S remained unchanged. These results represent a major purification of the chick intestinal receptor for 1,25-(OH)2D, an extremely rate and labile protein whose isolation is estimated to require a 200,000-fold purification. Affinity ligands such as DNA and blue dextran can effect major purification of this protein, lending credence to the hypothesis that the 1,25-(OH)2D receptor functions within the cell nucleus by altering the expression of specific genes.