Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P06889 (Mol)
 630,302 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

To clarify whether cigarette smoking during pregnancy causes an organic alteration in placental estrogen producing ability, we determined the catalytic activity of aromatase by the tritiated water assay, and tissue level of aromatase cytochrome P-450 (P-450arom) by the specific enzyme-linked immunosorbent assay, in placental samples from nonsmokers and smokers. As pregnancy progressed, both aromatase activity and P-450arom concentration increased in placentas from nonsmokers and smokers. However, the gradient of the increase was significantly less in heavy smokers (> or = 20 cigarettes a day) than in normal and moderate smokers (< 20 cigarettes a day). At term, the mean aromatase activity and P-450arom concentration in placentas from heavy smokers were significantly lower than in nonsmokers and moderate smokers, while aromatase activity per P-450arom (turnover rate) and the mean placental weight were comparable among the three groups. In contrast, the ratio of aryl hydrocarbon hydroxylase activity to aromatase activity was higher in placentas from heavy smokers. Immunohistochemical studies showed that P-450arom was localized in the cytoplasm of syncytiotrophoblasts of chorionic villi in placentas from both nonsmokers and smokers. These results suggest that the induction of placental P-450arom during gestation is suppressed by maternal smoking, resulting in a reduction in estrogen producing ability, while placental xenobiotic P-450 is induced.
J Steroid Biochem Mol Biol 1993 Jun
PMID:Cigarette smoking during pregnancy lowers aromatase cytochrome P-450 in the human placenta. 851 4

17 beta-Estradiol (E2) induces cathepsin D mRNA levels and intracellular levels of immunoreactive protein in MCF-7 human breast cancer cells. 2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) alone does not affect cathepsin D gene expression in this cell line; however, in cells cotreated with TCDD and E2, TCDD inhibited E2-induced cathepsin D mRNA levels, the rate of gene transcription, and levels of immunoreactive protein. The inhibitory responses were observed within 30 to 120 min after the cells were treated with TCDD. TCDD also inhibited E2-induced secreted alkaline phosphatase activity in aryl hydrocarbon (Ah)-responsive MCF-7 and wild-type mouse Hepa 1c1c7 cells cotransfected with the human estrogen receptor (hER) and the pBC12/S1/pac plasmid, which contains the 5' promoter region (-296/+57) of the cathepsin D gene and an alkaline phosphatase reporter gene. The E2-responsive ER/Sp1 sequence (-199 to -165) in the cathepsin D 5' region contains an imperfect GTGCGTG (-175/-181) xenobiotic responsive element (XRE); the role of this sequence in Ah responsiveness was investigated in gel electrophoretic mobility shift assays and with plasmid constructs containing a wild-type ER/Sp1 oligonucleotide or a mutant ER/Sp1-"XRE" oligonucleotide containing two C-->A mutations in the XRE sequence (antisense strand). In plasmid constructs which contained a chloramphenicol acetyltransferase reporter gene and the wild-type ER/Sp1 promoter sequence, E2-induced chloramphenicol acetyltransferase activity and mRNA levels were inhibited by TCDD whereas no inhibition was observed with the mutant ER/Sp1-"XRE" plasmids. Electrophoretic mobility shift assays showed that the nuclear or transformed cytosolic Ah receptor complex blocked formation of the ER-Sp1 complex with the wild-type but not the ER/Sp1 mutant oligonucleotide. Moreover, incubation of the wild-type bromodeoxyuridine-substituted ER/Sp1 oligonucleotide with the nuclear Ah receptor complex gave a specifically bound cross-linked 200-kDa band. These data demonstrate that Ah receptor-mediated inhibition of E2-induced cathepsin D gene expression is due to disruption of the ER-Sp1 complex by targeted interaction with an overlapping XRE.
Mol Cell Biol 1995 Dec
PMID:Molecular mechanism of inhibition of estrogen-induced cathepsin D gene expression by 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) in MCF-7 cells. 852 36

In an attempt to understand the evolution and role of flavin-containing monooxygenases (FMOs) in xenobiotic biotransformation by aquatic organisms, a survey of hepatic FMO activity (N,N-dimethylaniline N-oxidase and thiourea oxidase) was performed in one brackish water fish and 17 species of freshwater fish, one of which was anadromous. Only hepatic microsomes from the brackish water medaka (Oryzia latipes), the freshwater centrarid Lepomis macrochirus, and the anadromous rainbow trout (Oncorhynchus mykiss) consistently demonstrated FMO activity. Previous studies in trout have shown that the carbarmate insecticide, aldicarb, is bioactivated through an FMO-catalyzed S-oxidation. The toxicity of aldicarb was examined in O. mykiss and one of the species that did not show measurable FMO activity or protein, the channel catfish (Ictalurus punctatus). Rainbow trout were approximately 100 times more sensitive to aldicarb toxicity compared with channel catfish after a 96-hour waterborne exposure or 24 hours following intraperitoneal injection. However, rainbow trout were only 10 times more sensitive to aldicarb S-oxide, the bioactivated metabolite, than catfish 24 hours following intraperitoneal injection. Elimination profiles of injected aldicarb in both species fit a two-compartment model, but half-lives were significantly different between each species. Aldicarb and metabolites were rapidly cleared from trout (respective alpha and beta half-lives being 3 and 28 hr), while half-lives in catfish were significantly longer (alpha and beta half-lives being 16 and 140 hr). The major metabolite from catfish after 24 hours was aldicarb sulfone, which was 9.3% of the total dose. In trout, aldicarb sulfoxide was the major metabolite (7.6% of total dose) without any measurable sulfone. Because cytochrome P450 monooxygenases also perform the S-oxidation of aldicarb and differences in aldicarb disposition exist, future experiments will attempt to transfect catfish with rainbow trout FMO cDNA in order to determine the role of FMOs in aldicarb biotransformation and toxicity.
Mol Mar Biol Biotechnol 1995 Dec
PMID:Use of aquatic organisms as models to determine the in vivo contribution of flavin-containing monooxygenases in xenobiotic biotransformation. 854 83

Cu/Zn-superoxide dismutase (SOD)-accelerated oxidation of the benzene metabolite 1,4-hydroquinone (HQ) results in the enhanced formation of semiquinone anion radicals, electrophilic 1,4-benzoquinone (BQ), and H202. We selected bone marrow stromal cells and phiX-174 double stranded plasmid DNA as model systems to investigate the cytotoxicity and DNA cleaving activity of the Cu/Zn-SOD-mediated activation of HQ. The addition of either Cu/Zn-SOD or Min-SOD to the primary bone marrow stromal cell cultures significantly enhanced HQ-induced cytotoxicity, which could be completely prevented by adding reduced glutathione (GSH) or dithiothreitol but not be adding catalase. Incubation of the plasmid DNA with the HQ/Cu/Zn-SOD system resulted in the induction of single- as well as double-strand breaks, which could be inhibited by catalase and the Cu(I) chelators, bathocuproinedisulfonic acid (BCS) and GSH. Although Mn-SOD could enhance HQ-induced cytotoxicity to stromal cells, the activation of HQ by Mn-SOD did not contribute to the induction of DNA strand breaks. Similar to the HQ/Cu(II) and H202/Cu(II) systems, the DNA strand breaks mediated by HQ/Cu/Zn-SOD could not be effectively inhibited by the hydroxyl radical scavengers, including dimethylsulfoxide, mannitol, and 5,5-dimethyl-1-pyrroline N-oxide, but could be protected by sodium azide. Low-temperature electron spin resonance experiments showed that incubation of Cu/Znu-SOD with HQ resulted in the release of copper from the Cu/Zn-SOD, which could be prevented by catalase. Alpha-(4-Pyridyl-1-oxide)-N-tert-butylnitrone (POBN)/spin-trapping studies demonstrated that the interaction of HQ with Cu/Zn-SOD, but not with Mn-SOD, resulted in the significant formation of POBN-CH3 adduct in the presence of dimethylsulfoxide, suggesting the production of hydroxyl radical or its equivalent from this enzyme/xenobiotic interaction. The formation of the POBN-CH3 adduct from the HQ/Cu/Zn-SOD could be inhibited by catalase, BCS or GSH, indicating the important role for H202 and Cu(I) in the production of reactive oxygen species. Addition of human myeloperoxidase to the HQ/Cu/Zn-SOD synergistically enhanced the formation of BQ from HQ. This enhancement could be abolished by catalase. Taken together, these results demonstrate that activation of HQ by either Cu/Zn-SOD or Mn-SOD results in cytotoxicity to primary bone marrow stromal cells through the formation of electrophilic BQ. Interaction of HQ with Cu/Zn-SOD causes oxidative damage to Cu/Zn-SOD, leading to the release of copper from the enzyme. The further reaction between the released copper and H202 generates reactive oxygen species that participate in the induction of strand breaks in plasmid DNA. The H202 generated from the Cu/Zn-SOD-accelerated oxidation of HQ can also be utilized by myeloperoxidase resulting in additional conversion of HQ to BQ.
Mol Pharmacol 1996 Mar
PMID:Role of Cu/Zn-superoxide dismutase in xenobiotic activation. II. Biological effects resulting from the Cu/Zn-superoxide dismutase-accelerated oxidation of the benzene metabolite 1,4-hydroquinone. 864 80

We recently cloned a CYP2D subfamily member (CYP2D16) from a guinea pig adrenal cDNA library and investigated the expression of CYP2D16 in the guinea pig adrenal cortex and its relationship to adrenal xenobiotic metabolism. A modified sodium dodecyl sulfate-polyacrylamide gel electrophoresis technique revealed three major bands in the molecular mass range of cytochromes P450 in guinea pig adrenal microsomes. Two of the bands were immunoreactive with anti-CYP17 (54 kDa) or anti-CYP21 (52 kDa) antibody. The third band (50 kDa) was immunoreactive with antibody raised against CYP2D1 and with anti-CYP1A1/1A2 antibody. Microsequencing of the 50-kDa band yielded an amino-terminal sequence of 38 amino acids identical to that deducted from the CYP2D16 cDNA. In addition, Northern blot analyses indicated the CYP1A1 was not expressed in the adrenal gland, suggesting that only CYP2D16 composed the microsomal 50-kDa band. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis and Western blot analyses demonstrated greater expression of CYP2D16 in microsomes from the inner zone (zona reticularis) of the adrenal cortex than from the outer zones, coinciding with the major site of adrenal xenobiotic metabolism. Bufuralol-1'-hydroxylase activity, a marker for CYP2D isozymes, was also greater in inner- than in outer-zone microsomal preparations and was highly correlated with CYP2D16concentrations. Northern blot analysis with a full-length CYP2D16 cDNA as the probe gave strong bands with adrenal inner zone RNA preparations and relatively weak bands with outer zone RNA. CYP2D16 mRNA was also detectable in liver and kidney RNA preparations, but at lower levels than in the adrenal inner zone, and it was not detectable in testes, lung, intestines, or heart. Overall, the results demonstrate that CYP2D16 is expressed at highest levels in the inner zone of the guinea pig adrenal cortex and suggest a major role for this isozyme in adrenal xenobiotic metabolism.
Mol Pharmacol 1996 Mar
PMID:Expression and zonal distribution of CYP2D16 in the guinea pig adrenal cortex: relationship to xenobiotic metabolism. 864 85

Expression of CYP1A1 gene is regulated in a substrate-inducible manner through at least two kinds of regulatory DNA elements in addition to the TATA sequence, XRE (xenobiotic responsive element), and BTE (basic transcription element), a GC box sequence. The trans-acting factor on the XRE is a heterodimer consisting of arylhydrocarbon receptor (AhR) and AhR nuclear translocator (Arnt), while Sp1 acts as a regulatory factor on the BTE. We have investigated how these factors interact with one another to induce expression of the CYP1A1 gene. Both in vivo transfection assays using Drosophila Schneider line 2 (SL2) cells, which is devoid of endogenous Sp1, AhR, and Arnt, and in vitro transcription assays using baculovirus-expressed AhR, Arnt, and Sp1 proteins revealed that these factors enhanced synergistically expression of the reporter genes driven by a model CYP1A1 promoter, consisting of four repeated XRE sequences and a BTE sequence, in agreement with previous observation (Yanagida, A., Sogawa, K., Yasumoto, K., and Fujii-Kuriyama, Y. (1990) Mol. Cell. Biol. 10, 1470-1475). We have proved by coimmunoprecipitation assays and DNase I footprinting that both AhR and Arnt interact with the zinc finger domain of Sp1 via their basic HLH/PAS domains. When either the AhR.Arnt heterodimer of Sp1 was bound to its cognate DNA element, DNA binding of the second factor was facilitated. Survey of DNA sequences in the promoter region shows that the XRE and GC box elements are commonly found in the genes whose expressions are induced by polycyclic aromatic hydrocarbons, suggesting that the two regulatory DNA elements and their cognate trans-acting factors constitute a common mechanism for induction of a group of drug-metabolizing enzymes.
 ...
PMID:Cooperative interaction between AhR.Arnt and Sp1 for the drug-inducible expression of CYP1A1 gene. 864 31

The molecular mechanism of induction of cytochromes P4501A1/2 (CYP1A1/2) by a synthetic compound YH439 was studied in rodents as well as in cultured hepatoma cells. CYP1A1-mediated ethoxyresorufin-O-deethylase activity and amounts of its immunoreactive protein were increased in a time- and concentration-dependent manner after a single dose of YH439 (150 mg/kg). Northern blot analyses revealed that YH439 rapidly increased (< or = 2 hr) the levels of CYP1A1/2 mRNAs, resulting in an increase in CYP1A protein level by > 6-fold at 8 hr after injection. After YH439 administration, the levels of CYP1A1 and CYP1A2 mRNAs peaked at 8 hr and 16 hr, respectively, before returning to control levels at 16 and 24 hr. The CYP1A protein level, on the other hand, reached a maximum at 24 hr after YH439 treatment and returned to near-control levels at 72 hr. Nuclear run-on analyses revealed that YH439 induces CYP1A1/2 gene transcription as early as 2 hr after YH439 treatment. Cytosolic electrophoretic mobility shift assays suggested that YH439 activates the CYP1A1/2 genes through the aryl hydrocarbon (Ah) receptor and the xenobiotic response elements. The dependency on the Ah receptor for the induction of CYP1A1/2 by YH439 was confirmed by the lack of CYP1A1/2 induction in the Ah receptor knock-out mice (Ahr-1-) as well as in murine hepatoma cells without a functional Ah receptor. Molecular structural analysis of YH439 and several other compounds indicated that the planarity and size of a molecule are important in its interaction with the Ah receptor and subsequent CYP1A1/2 induction. YH439 is a thiazolium compound with little aromaticity and with a two-dimensional structure different from that of the Ahs. Therefore, it represents a new class of Ah receptor ligand and CYP1A inducer.
Mol Pharmacol 1996 Jun
PMID:Transcriptional induction of the cytochrome P4501A1 gene by a thiazolium compound, YH439. 864 58

We isolated mouse cDNA clones (Arnt2) that are highly similar to but distinct from the aryl hydrocarbon receptor (AhR) nuclear translocator (Arnt). The composite cDNA covered a 2,443-bp sequence consisting of a putative 2,136-bp open reading frame encoding a polypeptide of 712 amino acids. The predicted Arnt2 polypeptide carries a characteristic basic helix-loop-helix (bHLH)/PAS motif in its N-terminal region with close similarity (81% identity) to that of mouse Arnt and has an overall sequence identity of 57% with Arnt. Biochemical properties and interaction of Arnt2 with other bHLH/PAS proteins were investigated by coimmunoprecipitation assays, gel mobility shift assays, and the yeast two-hybrid system. Arnt2 interacted with AhR and mouse Sim as efficiently as Arnt, and the Arnt2-AhR complex recognized and bound specifically the xenobiotic responsive element (XRE) sequence. Expression of Arnt2 successfully rescued XRE-driven reporter gene activity in the Arnt-defective c4 mutant of Hepa-1 cells. RNA blot analysis revealed that expression of Arnt2 mRNA was restricted to the brains and kidneys of adult mice, while Arnt mRNA was expressed ubiquitously. In addition, whole-mount in situ hybridization of 9.5-day mouse embryos showed that Arnt2 mRNA was expressed in the dorsal neural tube and branchial arch 1, while Arnt transcripts were detected broadly in various tissues of mesodermal and endodermal origins. These results suggest that Arnt2 may play different roles from Arnt both in adult mice and in developing embryos. Finally, sequence comparison of the currently known bHLH/PAS proteins indicates a division into two phylogenetic groups: the Arnt group, containing Arnt, Arnt2, and Per, and the AhR group, consisting of AhR, Sim, and Hif-1alpha.
Mol Cell Biol 1996 Apr
PMID:cDNA cloning and tissue-specific expression of a novel basic helix-loop-helix/PAS factor (Arnt2) with close sequence similarity to the aryl hydrocarbon receptor nuclear translocator (Arnt). 865 46

Occupational exposure of floriculturists is characterized by alternating periods of intense pesticide spraying and reduced or no activity. Induction of sister chromatid exchanges (SCE), structural chromosome aberrations (CA) and micronuclei (MN) was investigated in peripheral lymphocytes of a group of 23 Italian floriculturists and 22 matched controls. Blood sampling was performed during and one month after the end of intensive pesticide treatments, in order to cover a period of high and low exposure, respectively. Each donor was genotyped for glutathione S-transferase M1 (GSTM1), T1 (GSTT1), and N-acetyltransferase 2 (NAT2), three polymorphic genes involved in xenobiotic metabolism, to assess their potential role in individual genotoxic response to the pesticide exposure. No effect of the pesticide exposure on the cytogenetic parameters were detected. Smoking, however, was found to increase SCE levels. The only significant influence of phenotype composition on cytogenetic response was an increase in SCE levels in the GSTT1 positive individuals compared with the GSTT1 nulls (P=0.02). This finding was, however, based on only four GSTT1 null donors (n=41 for GSTT1 positive donors). In addition, a possible interaction was observed between smoking and GSTM1 genotype in the CA assay, GSTM1 null smokers, earlier reported to have an elevated risk for lung cancer, showing higher CA frequencies than GSTM1 positive smokers.
Environ Mol Mutagen 1996
PMID:Cytogenetic monitoring of occupational exposure to pesticides: characterization of GSTM1, GSTT1, and NAT2 genotypes. 866 71

Twelve cytochrome P450 cDNA fragments were cloned from Drosophila melanogaster by reverse transcriptase/PCR (RT/PCR) using degenerate oligonucleotide primers. The corresponding genes belong to several subfamilies of the CYP4 and CYP9 P450 families. Only two of these genes, Cyp4dl and Cyp4d2, have previously been described. In situ hybridization of each of the cDNA fragments showed two clusters of genes; one near the tip of the X chromosome and the other on the left arm of chromosome 2. Interestingly the latter cluster comprises widely divergent genes belonging both to the CYP9 and CYP4 families and also to the CYP6 family (Cyp6a2). Putative allelic variants of several of the genes were found in different insecticide-resistant and -susceptible strains (Hikone R, Haag 79 and Oregon R). The identification of these genes and alleles will allow us to clarify the involvement of P450s in xenobiotic metabolism and will facilitate a genetic analysis of P450 functions in insects.
Mol Gen Genet 1996 Jun 12
PMID:Cytochrome P450 gene clusters in Drosophila melanogaster. 867 71


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