1,25-Dihydroxyvitamin D 3-stimulated mRNAs in rat small intestine

Abstract

The technique of differential hybridization has been employed to study gene expression associated with vitamin D action on the mammalian intestine. A cDNA library consisting of 10 6 independent recombinants was constructed from poly(A) + RNA extracted from vitamin D-deficient rats given 1,25-dihydroxyvitamin D 3. A survey of 20,000 clones resulted in identification of four distinct cDNAs whose corresponding mRNAs are significantly increased 12 h after an intrajugular dose of 1,25-dihydroxyvitamin D 3 given to vitamin D-deficient rats. DNA sequence analysis identified these mRNAs as (a) mitochondrial ATP synthetase, (b) vitamin D-dependent calcium binding protein, (c) cytochrome oxidase subunit I, and (d) cytochrome oxidase subunit III. The time course of response of three of these mRNAs was similar, with maximum values at 12 h after dosing, while that of cytochrome oxidase subunit I showed two peaks at 6 and 18 h following a single dose of 1,25-dihydroxyvitamin D 3. The levels of all four mRNAs were elevated in rats supplied with vitamin D when hypocalcemia was produced by dietary calcium restriction.