Mouse vitamin D-24-hydroxylase: molecular cloning, tissue distribution, and transcriptional regulation by 1alpha,25-dihydroxyvitamin D3

Endocrinology. 1997 Jun;138(6):2233-40. doi: 10.1210/endo.138.6.5170.

Abstract

Vitamin D-24-hydroxylase (24-OHase) is a cytochrome P-450 enzyme that catalyzes the conversion of 25-hydroxyvitamin D3 (25OHD3) and 1alpha,25-dihydroxyvitamin D3 [1,25-(OH)2D3] to 24,25-dihydroxyvitamin D3 and 1,24,25-trihydroxyvitamin D3, respectively. A full-length complementary DNA for mouse 24-OHase has now been characterized. The complementary DNA consists of 3309 bp and encodes a protein of 514 amino acids that shows 82% and 95% sequence identity with the human and rat enzymes, respectively. Northern blot analysis of tissues from mice injected with 1,25-(OH)2D3 (24 pmol/g) revealed that the 3.4-kb 24-OHase messenger RNA (mRNA) is most abundant in kidney and intestine, with smaller amounts present in skin, thymus, and bone. RT-PCR and Southern blot analysis detected 24-OHase mRNA in several other tissues including lung, testis, spleen, pancreas, and heart. Intraperitoneal injection of 1,25-(OH)2D3 induced dose- and time-dependent increases in both 24-OHase mRNA abundance and enzyme activity in mouse kidney. Similarly, 1,25-(OH)2D3-induced increases in both 24-OHase mRNA and activity were apparent in the duodenum. Although 1,25-(OH)2D3 increased the amount of 24-OHase mRNA in skin, enzyme activity was not detected in this tissue. Pretreatment of mice with cycloheximide (400 microg/g), an inhibitor of protein synthesis, potentiated the increase in 24-OHase mRNA abundance, but blocked the increase in 24-OHase activity, induced by 1,25-(OH)2D3 in kidney and duodenum, suggesting that 24-OHase gene expression may be regulated not only by the vitamin D receptor but also by a short-lived repressor protein.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Base Sequence
  • Calcitriol / pharmacology*
  • Cloning, Molecular
  • Cycloheximide / pharmacology
  • Cytochrome P-450 Enzyme System / biosynthesis*
  • Cytochrome P-450 Enzyme System / chemistry
  • Cytochrome P-450 Enzyme System / genetics
  • DNA, Complementary
  • Gene Expression Regulation, Enzymologic / drug effects*
  • Humans
  • Kidney / enzymology
  • Kinetics
  • Male
  • Mice
  • Mice, Inbred Strains
  • Molecular Sequence Data
  • Organ Specificity
  • Polymerase Chain Reaction
  • Rats
  • Sequence Homology, Amino Acid
  • Steroid Hydroxylases / biosynthesis*
  • Steroid Hydroxylases / chemistry
  • Steroid Hydroxylases / genetics
  • Transcription, Genetic / drug effects*
  • Vitamin D3 24-Hydroxylase

Substances

  • DNA, Complementary
  • Cytochrome P-450 Enzyme System
  • Cycloheximide
  • Steroid Hydroxylases
  • Vitamin D3 24-Hydroxylase
  • Calcitriol

Associated data

  • GENBANK/D89669