Circadian Expression of the Steroid 15 α-Hydroxylase (Cyp2a4) and Coumarin 7-Hydroxylase (Cyp2a5) Genes in Mouse Liver Is Regulated by the PAR Leucine Zipper Transcription Factor DBP

ABSTRACT To study the molecular mechanisms of circadian gene expression, we have sought to identify genes whose expression in mouse liver is regulated by the transcription factor DBP (albumin D-site-binding protein). This PAR basic leucine zipper protein accumulates according to a robust circadian rhythm in nuclei of hepatocytes and other cell types. Here, we report that the Cyp2a4 gene, encoding the cytochrome P450 steroid 15α-hydroxylase, is a novel circadian expression gene. This enzyme catalyzes one of the hydroxylation reactions leading to further metabolism of the sex hormones testosterone and estradiol in the liver. Accumulation of CYP2A4 mRNA in mouse liver displays circadian kinetics indistinguishable from those of the highly related CYP2A5 gene. Proteins encoded by both theCyp2a4 and Cyp2a5 genes also display daily variation in accumulation, though this is more dramatic for CYP2A4 than for CYP2A5. Biochemical evidence, including in vitro DNase I footprinting on the Cyp2a4 and Cyp2a5 promoters and cotransfection experiments with the human hepatoma cell line HepG2, suggests that the Cyp2a4 and Cyp2a5 genes are indeed regulated by DBP. These conclusions are corroborated by genetic studies, in which the circadian amplitude of CYP2A4 and CYP2A5 mRNAs and protein expression in the liver was significantly impaired in a mutant mouse strain homozygous for a dbp null allele. These experiments strongly suggest that DBP is a major factor controlling circadian expression of the Cyp2a4 and Cyp2a5genes in the mouse liver.

[1]  G. Gibbons,et al.  Diurnal variation in the activity of cholesterol 7α‐hydroxylase in the livers of fed and fasted rats , 1972, FEBS letters.

[2]  M. J. Coon,et al.  Preparation and properties of partially purified cytochrome P-450 and reduced nicotinamide adenine dinucleotide phosphate-cytochrome P-450 reductase from rabbit liver microsomes. , 1974, The Journal of biological chemistry.

[3]  van der Hoeven Ta,et al.  Preparation and Properties of Partially Purified Cytochrome P-450 and Reduced Nicotinamide Adenine Dinucleotide Phosphate-Cytochrome P-450 Reductase from Rabbit Liver Microsomes , 1974 .

[4]  I. Zucker,et al.  Circadian organization of the estrous cycle of the golden hamster. , 1976, Proceedings of the National Academy of Sciences of the United States of America.

[5]  L. P. Morin,et al.  Estradiol shortens the period of hamster circadian rhythms. , 1977, Science.

[6]  Howard M. Goodman,et al.  High resolution two-dimensional electrophoresis of basic as well as acidic proteins , 1977, Cell.

[7]  H. W. Norton,et al.  Daily rhythmicity of serum testosterone concentration in the male laboratory rat. , 1978, Endocrinology.

[8]  B. Howard,et al.  Recombinant genomes which express chloramphenicol acetyltransferase in mammalian cells , 1982, Molecular and cellular biology.

[9]  C. Walsh,et al.  Regioselectivity and stereoselectivity of androgen hydroxylations catalyzed by cytochrome P-450 isozymes purified from phenobarbital-induced rat liver. , 1983, The Journal of biological chemistry.

[10]  M. Negishi,et al.  Reciprocal regulation of sex-dependent expression of testosterone 15 alpha-hydroxylase (P-450(15 alpha)) in liver and kidney of male mice by androgen. Evidence for a single gene. , 1988, The Journal of biological chemistry.

[11]  U. Gubler.  A one tube reaction for the synthesis of blunt-ended double-stranded cDNA. , 1988, Nucleic acids research.

[12]  U. Schibler,et al.  A glycosylated liver-specific transcription factor stimulates transcription of the albumin gene , 1989, Cell.

[13]  N. Drinkwater,et al.  Promotion of murine hepatocarcinogenesis by testosterone is androgen receptor-dependent but not cell autonomous. , 1989, Proceedings of the National Academy of Sciences of the United States of America.

[14]  R. Lindberg,et al.  The structure and characterization of type I P-450(15) alpha gene as major steroid 15 alpha-hydroxylase and its comparison with type II P-450(15) alpha gene. , 1989, The Journal of biological chemistry.

[15]  J. Dunlap,et al.  Molecular cloning of genes under control of the circadian clock in Neurospora. , 1989, Science.

[16]  M. Noshiro,et al.  Rat liver cholesterol 7 alpha-hydroxylase. Pretranslational regulation for circadian rhythm. , 1990, The Journal of biological chemistry.

[17]  U. Schibler,et al.  Expression of the liver-enriched transcriptional activator protein DBP follows a stringent circadian rhythm , 1990, Cell.

[18]  U. Schibler,et al.  DBP, a liver-enriched transcriptional activator, is expressed late in ontogeny and its tissue specificity is determined posttranscriptionally , 1990, Cell.

[19]  Rat liver cholesterol 7 α-hydroxylase: pretranslational regulation for circadian rhythm Noshiro M, Nishimoto M, Okuda K. J Biol Chem 1990;265:10036–10041 , 1991 .

[20]  G. Labrecque,et al.  Biological rhythms in the absorption, distribution, metabolism and excretion of drugs. , 1991, Pharmacology & therapeutics.

[21]  R. Mason,et al.  Free radicals in toxicology. , 1993, Toxicology and applied pharmacology.

[22]  R. Feuers,et al.  Effects of caloric restriction on rodent drug and carcinogen metabolizing enzymes: implications for mutagenesis and cancer. , 1993, Mutation research.

[23]  C S Pittendrigh,et al.  Temporal organization: reflections of a Darwinian clock-watcher. , 1993, Annual review of physiology.

[24]  D. Lavery,et al.  Circadian transcription of the cholesterol 7 alpha hydroxylase gene may involve the liver-enriched bZIP protein DBP. , 1993, Genes & development.

[25]  Electrotransfer of microsomal cytochrome P450 after isoelectric focusing (IEF blots): resolution of human 2A and 3A isozymes. , 1994, Analytical biochemistry.

[26]  D. Waxman,et al.  Multiple, functional DBP sites on the promoter of the cholesterol 7 alpha-hydroxylase P450 gene, CYP7. Proposed role in diurnal regulation of liver gene expression. , 1994, The Journal of biological chemistry.

[27]  C. Bonfils,et al.  Overexpression of a cytochrome P-450 of the 2a family (Cyp2a-5) in chemically induced hepatomas from female mice. , 1994, European journal of biochemistry.

[28]  H. Pitot,et al.  Diurnal variation of the serine dehydratase mRNA level in rat liver. , 1994, Archives of biochemistry and biophysics.

[29]  U. Schibler,et al.  Cell size regulation, a mechanism that controls cellular RNA accumulation: consequences on regulation of the ubiquitous transcription factors Oct1 and NF-Y and the liver-enriched transcription factor DBP , 1995, The Journal of cell biology.

[30]  F. Fleury-Olela,et al.  The rat hepatic leukemia factor (HLF) gene encodes two transcriptional activators with distinct circadian rhythms, tissue distributions and target preferences. , 1995, The EMBO journal.

[31]  U. Schibler,et al.  DNA-binding specificity of PAR and C/EBP leucine zipper proteins: a single amino acid substitution in the C/EBP DNA-binding domain confers PAR-like specificity to C/EBP. , 1996, Biological chemistry.

[32]  N. Drinkwater,et al.  Two genes abrogate the inhibition of murine hepatocarcinogenesis by ovarian hormones. , 1996, Proceedings of the National Academy of Sciences of the United States of America.

[33]  G. Wanner,et al.  The two PAR leucine zipper proteins, TEF and DBP, display similar circadian and tissue‐specific expression, but have different target promoter preferences. , 1996, The EMBO journal.

[34]  A. Parkinson,et al.  Effects of caloric restriction on expression of testicular cytochrome P450 enzymes associated with the metabolic activation of carcinogens. , 1996, Archives of biochemistry and biophysics.

[35]  Ueli Schibler,et al.  The DBP gene is expressed according to a circadian rhythm in the suprachiasmatic nucleus and influences circadian behavior , 1997, The EMBO journal.

[36]  D. Lavery,et al.  Selective amplification via biotin- and restriction-mediated enrichment (SABRE), a novel selective amplification procedure for detection of differentially expressed mRNAs. , 1997, Proceedings of the National Academy of Sciences of the United States of America.

[37]  U. Schibler.  Circadian rhythms: New cogwheels in the clockworks , 1998, Nature.

[38]  Rudolf Jaenisch,et al.  Development : genetics, epigenetics, and environmental regulation , 1999 .

[39]  D. Lavery,et al.  Circadian Timing in Animals , 1999 .