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Karman BN, Basavarajappa MS, Craig ZR, Flaws JA. 2,3,7,8-Tetrachlorodibenzo-p-dioxin activates the aryl hydrocarbon receptor and alters sex steroid hormone secretion without affecting growth of mouse antral follicles in vitro. Toxicol Appl Pharmacol 2012; 261:88-96. [PMID: 22483799 DOI: 10.1016/j.taap.2012.03.015] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2012] [Revised: 03/19/2012] [Accepted: 03/21/2012] [Indexed: 11/17/2022]
Abstract
The persistent environmental contaminant, 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) is an ovarian toxicant. These studies were designed to characterize the actions of TCDD on steroidogenesis and growth of intact mouse antral follicles in vitro. Specifically, these studies tested the hypothesis that TCDD exposure leads to decreased sex hormone production/secretion by antral follicles as well as decreased growth of antral follicles in vitro. Since TCDD acts through binding to the aryl hydrocarbon receptor (AHR), and the AHR has been identified as an important factor in ovarian function, we also conducted experiments to confirm the presence and activation of the AHR in our tissue culture system. To do so, we exposed mouse antral follicles for 96 h to a series of TCDD doses previously shown to have effects on ovarian tissues and cells in culture, which also encompass environmentally relevant and pharmacological exposures (0.1-100 nM), to determine a dose response for TCDD in our culture system for growth, hormone production, and expression of the Ahr and Cyp1b1. The results indicate that TCDD decreases progesterone, androstenedione, testosterone, and estradiol levels in a non-monotonic dose response manner without altering growth of antral follicles. The addition of pregnenolone substrate (10 μM) restores hormone levels to control levels. Additionally, Cyp1b1 levels were increased by 3-4 fold regardless of the dose of TCDD exposure, evidence of AHR activation. Overall, these data indicate that TCDD may act prior to pregnenolone formation and through AHR transcriptional control of Cyp1b1, leading to decreased hormone levels without affecting growth of antral follicles.
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Affiliation(s)
- Bethany N Karman
- Department of Comparative Biosciences, University of Illinois at Urbana-Champaign, Urbana, IL 61802, USA
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2
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Basson AE, Dubery IA. Identification of a cytochrome P450 cDNA (CYP98A5) from Phaseolus vulgaris, inducible by 3,5-dichlorosalicylic acid and 2,6-dichloro isonicotinic acid. JOURNAL OF PLANT PHYSIOLOGY 2007; 164:421-8. [PMID: 16584810 DOI: 10.1016/j.jplph.2006.02.006] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/24/2006] [Accepted: 02/03/2006] [Indexed: 05/08/2023]
Abstract
To investigate the involvement of cytochrome P450s in the metabolism of plants treated with xenobiotic agrochemicals, bean leaves were treated with 3,5-dichlorosalicylic acid (DC-SA), a priming agent of plant defense and 2,6-dichloroisonicotinic acid (DC-INA), a chemical inducer of systemic acquired resistance. Through the use of directed differential display reverse transcription polymerase chain reactions, a differentially expressed cDNA amplicon, found to be up-regulated by both DC-SA and DC-INA treatment, was identified as a cytochrome P450 cDNA, CYP98A5. The nucleotide sequence indicates extensive homology to 3'-hydroxylases of p-coumaroyl esters. Dot blot analysis of leaves treated with various SA and isonicotinic acid derivatives showed enhanced expression of CYP98A5 due to DC-SA and DC-INA. Northern blot analysis of a time-dependent induction study of CYP98A5 in treated bean leaves indicated that DC-SA induces CYP98A5 mRNA transcripts earlier than DC-INA. Both inducers resulted in high transcript levels 24-48 h after treatment. The up-regulation of CYP98A5 is supportive of the conditioning and sensitizing effects of DC-SA and DC-INA to elicit a more rapid and effective defense response.
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MESH Headings
- Amino Acid Sequence
- Base Sequence
- Chlorobenzoates
- Cloning, Molecular
- Cytochrome P-450 Enzyme System/biosynthesis
- Cytochrome P-450 Enzyme System/genetics
- DNA Primers/genetics
- DNA, Complementary/genetics
- DNA, Complementary/isolation & purification
- DNA, Plant/genetics
- DNA, Plant/isolation & purification
- Enzyme Induction/drug effects
- Genes, Plant/drug effects
- Isonicotinic Acids/pharmacology
- Molecular Sequence Data
- Phaseolus/drug effects
- Phaseolus/enzymology
- Phaseolus/genetics
- Plant Leaves/drug effects
- Plant Leaves/enzymology
- Polymerase Chain Reaction
- RNA, Messenger/genetics
- RNA, Messenger/metabolism
- RNA, Plant/genetics
- RNA, Plant/metabolism
- Salicylates/pharmacology
- Sequence Homology, Amino Acid
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Affiliation(s)
- Adriaan E Basson
- Department of Biochemistry, University of Johannesburg, Kingsway Campus, Auckland Park 2006, South Africa
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3
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David JP, Boyer S, Mesneau A, Ball A, Ranson H, Dauphin-Villemant C. Involvement of cytochrome P450 monooxygenases in the response of mosquito larvae to dietary plant xenobiotics. INSECT BIOCHEMISTRY AND MOLECULAR BIOLOGY 2006; 36:410-20. [PMID: 16651188 DOI: 10.1016/j.ibmb.2006.02.004] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/07/2005] [Revised: 02/27/2006] [Accepted: 02/28/2006] [Indexed: 05/08/2023]
Abstract
The response of mosquito larvae to plant toxins found in their breeding sites was investigated by using Aedes aegypti larvae and toxic arborescent leaf litter as experimental models. The relation between larval tolerance to toxic leaf litter and cytochrome P450 monooxygenases (P450s) was examined at the toxicological, biochemical and molecular levels. Larvae pre-exposed to toxic leaf litter show a higher tolerance to those xenobiotics together with a strong increase in P450 activity levels. This enzymatic response is both time- and dose-dependent. The use of degenerate primers from various P450 genes (CYPs) allowed us to isolate 16 new CYP genes belonging to CYP4, CYP6 and CYP9 families. Expression studies revealed a 2.3-fold over-expression of 1 CYP gene (CYP6AL1) after larval pre-exposure to toxic leaf litter, this gene being expressed at a high level in late larval and pupal stages and in fat bodies and midgut. The CYP6AL1 protein has a high level of identity with other insect's CYPs involved in xenobiotic detoxification. The role of CYP genes in tolerance to natural xenobiotics and the importance of such adaptive responses in the capacity of mosquitoes to colonize new habitats and to develop insecticide resistance mechanisms are discussed.
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Affiliation(s)
- J P David
- Laboratoire d'Ecologie Alpine (LECA) UMR 5553, Bâtiment D, rue de la piscine, Université Joseph Fourier, BP53, 38041 Grenoble cedex 9, France.
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4
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Skaanild MT, Friis C. Cytochrome P450 sex differences in minipigs and conventional pigs. PHARMACOLOGY & TOXICOLOGY 1999; 85:174-80. [PMID: 10563516 DOI: 10.1111/j.1600-0773.1999.tb00088.x] [Citation(s) in RCA: 90] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Minipigs have become a popular alternative to the traditional non-rodent species although little information is available on their P450 system. The total P450, the enzyme activity and immunochemical levels of some of the most important drug metabolizing isoenzymes CYP1A2, CYP2A6, CYP2C19, CYP2D6, CYP2E1 and CYP3A4 were measured in liver microsomes from 8 minipigs and 12 conventional pigs of both sexes and castrate conventional pigs. The mRNA expression was analyzed for 3 isoenzymes: CYP1A2, CYP2A6 and CYP2E1. The total P450 activity was slightly higher in minipigs compared to conventional pigs but no sex differences were detected. CYP1A2 activity was 4 times higher in female than in male minipigs. The activity of the male minipigs possessed the same activity as were identical to the conventional females, males and castrates. The activity of CYP2E1 was 4 times higher in female than in male minipigs and 2 times higher in female than in male pigs. No activity of CYP2D6 or CYP2C19 could be detected. The CYP3A4 activity detected in minipigs was higher than the activity in conventional pigs. A slight sex difference was seen in both strains. Correlations between enzyme activity and immunochemical levels were found for CYP1A2, CYP2A6 and CYP3A4 but not for CYP2E1. The mRNA concentration of CYP1A2, CYP2A6 and CYP2E1 was determined because the activity of these enzymes showed marked sex differences. A Spearman ranking correlation analysis between mRNA expression and enzyme activity showed a weak correlation for CYP2A6, but not for CYP1A2 and CYP2E1. These results seem to indicate that CYP2A6 could be transcriptionally regulated, whereas CYP1A2 might be post-transcriptionally regulated.
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Affiliation(s)
- M T Skaanild
- Department of Pharmacology and Pathobiology, The Royal Veterinary and Agricultural University, Copenhagen, Denmark
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5
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Piscaglia F, Knittel T, Kobold D, Barnikol-Watanabe S, Di Rocco P, Ramadori G. Cellular localization of hepatic cytochrome 1B1 expression and its regulation by aromatic hydrocarbons and inflammatory cytokines. Biochem Pharmacol 1999; 58:157-65. [PMID: 10403529 DOI: 10.1016/s0006-2952(99)00066-0] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
Cytochrome P450 1B1 (CYP1B1) is an activator of several xenobiotics and is induced in the liver upon experimental exposure to aromatic hydrocarbons. Since its cellular localization and regulation are incompletely clarified, Cyp1B1 expression and inducibility by 9,10-dimethyl-1,2-benzanthracene (DMBA) and inflammatory cytokines were investigated in different rat liver cell populations in vitro and in the liver during hepatocellular injury. Expression of Cyp1B1 was studied by Northern blot analysis in hepatic stellate cells (HSCs), myofibroblasts (MFs), Kupffer cells (KCs), and hepatocytes at various time points of primary cultures and in acutely damaged rat liver (carbon tetrachloride model). Enzyme inducibility was assessed by incubation of cells with DMBA as well as, in the case of HSCs, with tumor necrosis factor-alpha (TNF-alpha) and transforming growth factor beta1 (TGFbeta1). Cyp1B1 messengers were expressed at high levels by HSCs and MFs, whereas constitutive expression was not detectable in KCs or in hepatocytes. Cyp1B1-specific mRNA were expressed at highest levels in HSCs at an early stage of activation (2 days after plating) and were diminished upon further activation. DMBA strongly enhanced Cyp1B1 gene expression in HSCs, MFs, and in hepatocytes at day 3 of primary cultures, but not in hepatocytes at day 1, or in KCs. The inflammatory cytokine TNF-alpha enhanced the Cyp1B1 gene expression in HSCs, either when administered alone or in addition to DMBA, while TGFbeta1 did not affect Cyp1B1 expression, even after DMBA induction. We conclude that HSCs and MFs seem to be the major cellular sources of hepatic Cyp1B1 expression and that the constitutive expression of the Cyp1B1 gene and the responsiveness to DMBA stimulation differ between mesenchymal and parenchymal liver cells, indicating a cell-specific regulation of Cyp1B1 gene expression. Interestingly, TNF-alpha is a potent stimulator of the Cyp1B1 gene in HSCs and acts in concert with DMBA.
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Affiliation(s)
- F Piscaglia
- Department of Internal Medicine, University of Göttingen, Germany
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6
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Zhang L, Savas U, Alexander DL, Jefcoate CR. Characterization of the mouse Cyp1B1 gene. Identification of an enhancer region that directs aryl hydrocarbon receptor-mediated constitutive and induced expression. J Biol Chem 1998; 273:5174-83. [PMID: 9478971 DOI: 10.1074/jbc.273.9.5174] [Citation(s) in RCA: 103] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Transcriptional activation of the Cyp1B1 gene in rodents is stimulated by both polycyclic hydrocarbons and cAMP. The mouse Cyp1B1 gene structure contains three exons, of which the second nucleotide of exon 2 is the translation start site. Primer extension analysis identified a transcription start domain defining an exon 1 of 371 base pairs. The sequence 1.075 kilobases upstream of the transcription start site showed 11 xenobiotic-responsive elements (XRE) (TnGCGTG or GCGTG) that are putative aryl hydrocarbon receptor (AhR)-binding sites and three steroidogenic factor-1 motifs that are associated with cAMP-mediated transcriptional activation of genes. A transiently transfected Cyp1B1-luciferase construct, composed of exon 1 and 1.075 kilobases of 5'-flanking region, was induced by 2,3, 7,8-tetrachlorodibenzo-p-dioxin (TCDD; 10.0 +/- 3.0-fold, n = 6) in C3H10T1/2 cells, which exclusively express Cyp1B1. The 90-base pair basal promoter contains two SP-1 sites, one SF-1 site, and a TATA-like box. TCDD induction and basal expression were dependent on positive regulatory elements present between -1075 and -810. Five XRE motifs localized in the enhancer region were completely conserved between mouse and human CYP1B1 sequences. Similar inductions were seen in Hepa-1 cells, which express Cyp1A1 but not Cyp1B1. However, basal Cyp1B1 promoter activities were 4-10-fold higher in C3H10T1/2 cells providing the enhancer region was present, partially reproducing the in vivo cell-specific expression of Cyp1B1. Gel shift experiments established that TCDD stimulates AhR binding to the downstream XRE in the enhancer region. However, oligonucleotides that encompass two other XREs show a high affinity complex of similar size that is evident even without TCDD treatment and that does not contain either the AhR or AhR nuclear translocator. The fourth XRE is immediately adjacent to an E-box, and this oligonucleotide formed a smaller complex that was dependent on this E-box sequence. Negative regulatory sequences have been located between the promoter and TCDD-responsive enhancer regions. Constitutive expression of the Cyp1B1 gene was lost in AhR-deficient cells and was restored by transfected AhR cDNA. Reporter constructs function in a parallel manner, demonstrating the key role of the AhR in constitutive as well as TCDD-induced expression of Cyp1B1 in mouse embryo fibroblasts.
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MESH Headings
- Animals
- Aryl Hydrocarbon Hydroxylases
- Base Sequence
- Binding Sites
- Conserved Sequence
- Cytochrome P-450 CYP1B1
- Cytochrome P-450 Enzyme System/genetics
- Embryo, Mammalian/cytology
- Enhancer Elements, Genetic
- Enzyme Induction
- Fibroblasts/cytology
- Gene Expression Regulation, Enzymologic
- Genes, Reporter
- Genomic Library
- Humans
- Mice
- Molecular Sequence Data
- Nuclear Proteins/metabolism
- Polychlorinated Dibenzodioxins/pharmacology
- Promoter Regions, Genetic
- Protein Binding
- RNA, Messenger/biosynthesis
- Receptors, Aryl Hydrocarbon/metabolism
- Sequence Analysis, DNA
- Sequence Homology, Nucleic Acid
- Species Specificity
- Steroidogenic Factor 1
- Transcription, Genetic
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Affiliation(s)
- L Zhang
- Department of Pharmacology, Medical Science Center, University of Wisconsin, Madison, Wisconsin 53706, USA
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7
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Villard PH, Seree EM, Re JL, De Meo M, Barra Y, Attolini L, Dumenil G, Catalin J, Durand A, Lacarelle B. Effects of tobacco smoke on the gene expression of the Cyp1a, Cyp2b, Cyp2e, and Cyp3a subfamilies in mouse liver and lung: relation to single strand breaks of DNA. Toxicol Appl Pharmacol 1998; 148:195-204. [PMID: 9473526 DOI: 10.1006/taap.1997.8332] [Citation(s) in RCA: 49] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Cigarette smoking is a worldwide health problem and is the greatest risk factor for lung cancer. By activating procarcinogens, hepatic and extrahepatic cytochromes P450 can participate in lung carcinogenesis. Tobacco smoke contains numerous cytochrome P450 inducers, substrates, and inhibitors. In the present study we investigated, in male NMRI mice, the effects of cigarette smoke on hepatic and pulmonary cytochrome P450 expression and their possible role in the induction of DNA lesions such as DNA single strand breaks (SSB). Hepatic and pulmonary mouse cytochrome P450 isozymes involved in carcinogenesis (Cyp1a, 2b, 2e, 3a) were differently induced by cigarette smoke. Cyp2e1 mRNA was dramatically enhanced (12.7-fold increase) while Cyp2b10 mRNA remained unchanged and Cyp1a1 was decreased or not detected. Cyp3a protein and mRNA were not detected in lung, suggesting that this isozyme is not expressed in mouse pulmonary tissue. The SSB of DNA increased in lung and liver treated mice. In contrast no modification was observed in lymphocytes that barely expressed cytochromes P450. Cimetidine and propylene glycol reduced SSB of DNA induced by smoking in liver and lung cells. The inhibition (-70%) observed in lung following treatment by propylene glycol, a CYP2E1 inhibitor, suggested that this isozyme is at least in part involved in pulmonary DNA damage induced by tobacco smoke. The high concentration of CYP2E1 function and regulation in mammals suggests that this protein could be involved in pulmonary carcinogenesis in human smokers.
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Affiliation(s)
- P H Villard
- Faculté de Pharmacie, Université de la Méditerranée, 27 Bd. Jean Moulin, Marseille Cedex 5, 13385, France
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8
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Shinki T, Shimada H, Wakino S, Anazawa H, Hayashi M, Saruta T, DeLuca HF, Suda T. Cloning and expression of rat 25-hydroxyvitamin D3-1alpha-hydroxylase cDNA. Proc Natl Acad Sci U S A 1997; 94:12920-5. [PMID: 9371776 PMCID: PMC24239 DOI: 10.1073/pnas.94.24.12920] [Citation(s) in RCA: 155] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
A full-length cDNA for the rat kidney mitochondrial cytochrome P450 mixed function oxidase, 25-hydroxyvitamin D3-1alpha-hydroxylase (P4501alpha), was cloned from a vitamin D-deficient rat kidney cDNA library and subcloned into the mammalian expression vector pcDNA 3.1(+). When P4501alpha cDNA was transfected into COS-7 transformed monkey kidney cells, they expressed 25-hydroxyvitamin D3-1alpha-hydroxylase activity. The sequence analysis showed that P4501alpha was of 2,469 bp long and contained an ORF encoding 501 amino acids. The deduced amino acid sequence showed a 53% similarity and 44% identity to the vitamin D3-25-hydroxylase (CYP27), whereas it has 42.6% similarity and 34% identity with the 25-hydroxyvitamin D3-24-hydroxylase (CYP24). Thus, it composes a new subfamily of the CYP27 family. Further, it is more closely related to the CYP27 than to the CYP24. The expression of P4501alpha mRNA was greatly increased in the kidney of vitamin D-deficient rats. In rats with the enhanced renal production of 1alpha,25-dihydroxyvitamin D3 (rats fed a low Ca diet), P4501alpha mRNA was greatly increased in the renal proximal convoluted tubules.
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Affiliation(s)
- T Shinki
- Department of Biochemistry, School of Dentistry, Showa University, Tokyo, Japan.
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9
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Wo YY, Stewart J, Greenlee WF. Functional analysis of the promoter for the human CYP1B1 gene. J Biol Chem 1997; 272:26702-7. [PMID: 9334254 DOI: 10.1074/jbc.272.42.26702] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Our laboratory has cloned the cDNA (Sutter, T. R., Tang, Y. M., Hayes, C. L., Wo, Y.-Y. P., Jabs, E. W., Li, X., Yin, H., Cody, C. W. , and Greenlee, W. F. (1994) J. Biol. Chem. 269, 13092-13099) and gene (Tang, Y. M., Wo, Y.-Y. P., Jabs, E. W., Stewart, J. C., Sutter, T. R., and Greenlee, W. F. (1996) J. Biol. Chem. 271, 28324-28330) for human CYP1B1, a new member of the cytochrome P450 superfamily. Here, we report on the mapping and function of the CYP1B1 promoter. The CYP1B1 promoter is fully functional, when it is uncoupled from upstream enhancer elements. Deletion analysis and site-directed mutagenesis identified four regulatory elements required for maximum promoter activity: two antisense Sp1 sites (-84 to -89 and -68 to -73), a TATA-like box (-34 to -29), and an initiator motif (-5 to +3). The initiator and the TATA-like elements are both required for basal promoter activity, with enhanced activity mediated by the two antisense Sp1 elements. The CYP1B1 initiator was demonstrated by in vitro transcription analysis to be a positioning element that maintained fidelity of transcription from a single site. Specific binding to a CYP1B1 initiator probe by human nuclear extract proteins was competed either by the highly homologous murine terminal deoxynucleotidyl transferase initiator or, to a lesser extent, by the adenovirus major late initiator. Taken together, these results indicate that the structure and function of the CYP1B1 promoter confers constitutive expression of the gene and assures fidelity of transcription initiation from a single site. The CYP1B1 promoter is distinct from the promoters of the closely related cytochrome P450s CYP1A1 and CYP1A2 and is structurally and functionally similar to the promoters of constitutively expressed genes and at least two viruses.
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Affiliation(s)
- Y Y Wo
- Department of Molecular Pharmacology and Medicinal Chemistry, Purdue University, West Lafayette, Indiana 47907, USA
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10
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Kullman SW, Matsumura F. Identification of a novel cytochrome P-450 gene from the white rot fungus Phanerochaete chrysosporium. Appl Environ Microbiol 1997; 63:2741-6. [PMID: 9212420 PMCID: PMC168569 DOI: 10.1128/aem.63.7.2741-2746.1997] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
A gene fragment belonging to the cytochrome P-450 superfamily has been cloned and identified from stationary cultures of the filamentous fungus Phanerochaete chrysosporium by reverse transcriptase (RT)-PCR. A set of degenerate primers homologous to highly conserved regions of known cytochrome P-450 sequences were used for initial RT-PCRs. Individual PCR products were cloned, sequenced, and identified as those belonging to the cytochrome P-450 superfamily based on amino acid sequence homologies and the presence of the highly conserved heme binding region. The nucleotide sequence of a single cDNA clone indicated the presence of an open reading frame encoding a partial cytochrome P-450 protein of 208 amino acids. Comparisons of the deduced amino acid sequence of the partial protein to other known cytochrome P-450 sequences indicate that it is the first member of a new family of cytochrome P-450s, designated CYP63-1A. Northern blot analysis suggests that CYP63-1A is expressed under both nitrogen-rich and nitrogen-deficient culture conditions and thus not under the same regulatory constraints as the well-studied lignin and manganese peroxidases. Western blot analyses using antibodies raised to the heme binding region of CYP63-1A indicate that the protein has a molecular mass of approximately 44,000 Da.
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Affiliation(s)
- S W Kullman
- Department of Environmental Toxicology, University of California, Davis 95616, USA
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11
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Tang YM, Wo YY, Stewart J, Hawkins AL, Griffin CA, Sutter TR, Greenlee WF. Isolation and characterization of the human cytochrome P450 CYP1B1 gene. J Biol Chem 1996; 271:28324-30. [PMID: 8910454 DOI: 10.1074/jbc.271.45.28324] [Citation(s) in RCA: 155] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
Previously, we identified a novel human cytochrome P450 cDNA that is inducible by 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) and represents the first member of a new subfamily designated cytochrome P4501B1 (CYP1B1; Sutter, T. R., Tang, Y. M., Hayes, C. L., Wo, Y. P., Jabs, E. W., Li, X., Yin, H., Cody, C. W., and Greenlee, W. F. (1994) J. Biol. Chem. 269, 13092-13099). Here, we report on the isolation and initial characterization of the CYP1B1 gene. The CYP1B1 gene maps to human chromosome 2 at 2p21-22 and contains three exons and two introns. The putative open reading frame starts in the second exon and is 1629 base pairs in length. Southern analysis using DNA probes directed to each of the three exons confirmed that CYP1B1 is a single copy gene. Human CYP1B1 differs from its two most closely related members of the cytochrome P450 superfamily, CYP1A1 and CYP1A2, in the number of exons (3 versus 7) and chromosome location (2 versus 15). A single transcription initiation site was identified by primer extension analysis and S1 nuclease mapping. Based on nucleotide sequence analysis, the CYP1B1 gene lacks a consensus TATA box in the promoter region and contains nine TCDD-responsive enhancer core binding motifs (5'-GCGTG-3') located within a 2.5-kilobase pair genomic fragment 5'-ward of the transcription initiation start site. Deletion analysis of chloramphenicol acetyltransferase reporter gene constructs containing 5' CYP1B1 genomic fragments indicates that a region from -1022 to -835 containing three of the nine core binding motifs contributes to the TCDD-inducible expression of CYP1B1.
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Affiliation(s)
- Y M Tang
- Department of Pharmacology and Toxicology, Purdue University, West Lafayette, Indiana 47907, USA
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12
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Bhattacharyya KK, Brake PB, Eltom SE, Otto SA, Jefcoate CR. Identification of a rat adrenal cytochrome P450 active in polycyclic hydrocarbon metabolism as rat CYP1B1. Demonstration of a unique tissue-specific pattern of hormonal and aryl hydrocarbon receptor-linked regulation. J Biol Chem 1995; 270:11595-602. [PMID: 7744798 DOI: 10.1074/jbc.270.19.11595] [Citation(s) in RCA: 120] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Antibodies against a novel adrenocorticotropic hormone-inducible cytochrome P450 (P450RAP), responsible for polycyclic aromatic hydrocarbon metabolism in rat adrenal microsomes (Otto, S., Bhattacharyya, K.K., and Jefcoate, C.R. (1992) Endocrinology 131, 3067-3076), identified a cDNA clone encoding a partial cytochrome P450 sequence from a rat adrenal cDNA library. Rescreening a second cDNA library yielded several clones up to 5.0 kilobases (kb) encoding a 1629-base pair open reading frame. The deduced amino acid sequence (543 residues) matched completely with five peptides cleaved from P450RAP. The amino acid sequence of P450RAP is 92% identical to a 2,3,7,8-tetrachlorodibenzo-p-dioxin-inducible CYP1B1, cloned from mouse C3H10T1/2 (10T1/2) embryo fibroblast cells (Savas, U., Bhattacharyya, K. K., Christou, M., Alexander, D.L., and Jefcoate, C. R. (1994) J. Biol. Chem. 269, 14905-14911), which shows nearly the same characteristics in polycyclic aromatic hydrocarbon metabolism. The available 5'- and 3'-noncoding regions show, respectively, 93 and 83% sequence identity. We conclude that P450RAP protein is encoded by a rat CYP1B1 gene orthologous to the mouse CYP1B1 gene. Alignment of rat CYP1B1 amino acid sequences with rat CYP1A1 (39% identical) indicated eight regions of high identity for each (60-78%), interspersed by extensive regions of less than 30% similarity. The CYP1B1 cDNAs hybridize a 5.2-kb mRNA in rat adrenals, consistent with the length of the longest clones and the mRNA recognized in 10T1/2 cells. CYP1B1 mRNA was elevated by a 2-day adrenocorticotropic hormone treatment but much less than CYP11A1 (cytochrome P450 side chain cleavage) mRNA (2-fold versus 4-fold). The lower levels of the 5.2-kb mRNA in other steroidogenic cells (ovary) was consistent with the amount of immunodetectable CYP1B1 protein and, unlike the adrenal, expression in the ovary was stimulated 5-fold by beta-naphthoflavone, an aryl hydrocarbon receptor agonist, in parallel with CYP1A1 induction. In several other tissues (liver > lung > uterus >> kidney), CYP1B1 mRNA and protein were constitutively undetectable but highly induced by beta-naphthoflavone, although at much lower levels than CYP1A1. Rat CYP1B1, therefore, exhibits regulation through hormonal signaling and the aryl hydrocarbon receptor in a cell-specific manner.
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Affiliation(s)
- K K Bhattacharyya
- Department of Pharmacology, University of Wisconsin Medical School, Madison 53706, USA
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Shen Z, Denison K, Lobb R, Gatewood JM, Chen DJ. The human and mouse homologs of the yeast RAD52 gene: cDNA cloning, sequence analysis, assignment to human chromosome 12p12.2-p13, and mRNA expression in mouse tissues. Genomics 1995; 25:199-206. [PMID: 7774919 DOI: 10.1016/0888-7543(95)80126-7] [Citation(s) in RCA: 51] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
The yeast Saccharomyces cerevisiae RAD52 gene is involved in DNA double-strand break repair and mitotic/meiotic recombination. The N-terminal amino acid sequence of yeast S. cerevisiae, Schizosaccharomyces pombe, and Kluyveromyces lactis and chicken is highly conserved. Using the technology of mixed oligonucleotide primed amplification of cDNA (MOPAC), two mouse RAD52 homologous cDNA fragments were amplified and sequenced. Subsequently, we have cloned the cDNA of the human and mouse homologs of yeast RAD52 gene by screening cDNA libraries using the identified mouse cDNA fragments. Sequence analysis of cDNA derived amino acid revealed a highly conserved N-terminus among human, mouse, chicken, and yeast RAD52 genes. The human RAD52 gene was assigned to chromosome 12p12.2-p13 by fluorescence in situ hybridization, R-banding, and DNA analysis of somatic cell hybrids. Unlike chicken RAD52 and mouse RAD51, no significant difference in mouse RAD52 mRNA level was found among mouse heart, brain, spleen, lung, liver, skeletal muscle, kidney, and testis. In addition to an approximately 1.9-kb RAD52 mRNA band that is present in all of the tested tissues, an extra mRNA species of approximately 0.85 kb was detectable in mouse testis.
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Affiliation(s)
- Z Shen
- Life Sciences Division, Los Alamos National Laboratory, New Mexico 87545, USA
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Shen Z, Liu J, Wells RL, Elkind MM. cDNA cloning, sequence analysis, and induction by aryl hydrocarbons of a murine cytochrome P450 gene, Cyp1b1. DNA Cell Biol 1994; 13:763-9. [PMID: 7772257 DOI: 10.1089/dna.1994.13.763] [Citation(s) in RCA: 46] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
C3H mouse embryo fibroblast cells, designated 10T1/2, can be transformed by physical and chemical agents including polycyclic aromatic hydrocarbons. In a previous report (Shen et al., Proc. Natl. Acad. Sci. USA 90, 11483-11487, 1993), we identified a cytochrome P450 gene induced by polycyclic aromatic hydrocarbons (PAHs) that is different from 1A1 or 1A2, and which we tentatively named P450CMEF. Here, we report the entire cDNA sequence of P450CMEF (5,128 bp) and the amino acid sequence deduced from it (543 residues). A comparison of the latter sequence with known cytochrome P450s indicates that P450CMEF is in a new subfamily of family 1 of the P450 superfamily. Accordingly, the Committee on Standardized Cytochrome P450 Nomenclature designated the gene Cyp1b1. Exposure to various aryl hydrocarbons (2.5 hr) induced Cyp1b1 mRNA in 10T1/2 cells to different degrees: 2,3,7,8-tetrachlorodibenzo-p-dioxin, 7,12-dimethylbenz[a]anthracene, benz[a]anthracene, benzo[a]pyrene, and beta-naphthoflavone were strong inducers; alpha-naphthoflavone and 3-methylcholanthrene, were moderate inducers; and benzo[e]pyrene was a weak inducer.
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Affiliation(s)
- Z Shen
- Department of Radiological Health Sciences, Colorado State University, Fort Collins 80523, USA
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Savas U, Bhattacharyya K, Christou M, Alexander D, Jefcoate C. Mouse cytochrome P-450EF, representative of a new 1B subfamily of cytochrome P-450s. Cloning, sequence determination, and tissue expression. J Biol Chem 1994. [DOI: 10.1016/s0021-9258(17)36551-1] [Citation(s) in RCA: 70] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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