Receptor-positive hereditary resistance to 1, 25-dihydroxyvitamin d: Chromatography of hormone-receptor complexes on deoxyribonucleic acid-cellulose shows two classes of mutation

We used cultured skin fibroblasts from patients with hereditary resistance to 1, 25-dihydroxyvitamin D [1, 25-(OH)₂D] and normal hormone binding to soluble extract from cells [i.e. receptor-positive resistance to 1, 25(OH)₂D] to characterize DNA binding of the receptor for 1, 25-(OH)₂D. Occupied receptor was generated by incubating soluble extracts from cells with [³H]1, 25-(OH)₂D₃; occupied receptor was applied to columns of DNA-cellulose and then eluted with linear gradients of KC1. Occupied receptors of cells from other sources eluted as a single peak at 0.20-0.26 M KC1; this elution pattern was independent of tissue (skin, breast cancer, or osteosarcoma) or species (human or rat) of origin of the receptors. With cells from two kindreds in whom there was mildly decreased localization of the hormone-receptor complex to the nucleus in vitro, occupied receptor interacted abnormally with DNA-cellulose (elution at 0.0-0.13 M KC1 vs. normal at 0.20-0.26 M KC1); this suggested mutation(s) that affected a DNA-binding domain of the receptor in these two kindreds. With receptor-positive cells from two other kindreds in whom there was unmeasurable hormone localization to the nucleus, the elution pattern of occupied receptors from DNA-cellulose was normal; this suggested mutation(s) which did not affect the same DNA-binding site. We conclude that our demonstration of two distinct elution profiles from DNA-cellulose reflects two independent classes of mutation, either of which can cause receptor-positive resistance to 1, 25-(OH)₂D.