Regulation of calcium-binding protein messenger RNA by 1,25-dihydroxycholecalciferol.

1,25-Dihydroxycholecalciferol modulates the synthesis of the intestinal calcium-binding protein. To determine if this effect is due to an increase in calcium-binding protein mRNA activity, we measured total cytoplasmic protein-specific mRNA activity from chick intestine in an in vitro wheat germ translation system. 1,25-Dihydroxycholecalciferol enhances calcium-binding protein specific mRNA activity. The sterol does not induce a general increase in mRNA synthesis since the concentration of only a few proteins increased. Thus 1,25-dihydroxycholecalciferol regulates only a subset of genes and specifically affects a transcriptional process involving calcium-binding protein synthesis.