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Abstract
Significant advances have taken place in our knowledge of the enzymes involved in steroid hormone biosynthesis since the last comprehensive review in 1988. Major developments include the cloning, identification, and characterization of multiple isoforms of 3beta-hydroxysteroid dehydrogenase, which play a critical role in the biosynthesis of all steroid hormones and 17beta-hydroxysteroid dehydrogenase where specific isoforms are essential for the final step in active steroid hormone biosynthesis. Advances have taken place in our understanding of the unique manner that determines tissue-specific expression of P450aromatase through the utilization of alternative promoters. In recent years, evidence has been obtained for the expression of steroidogenic enzymes in the nervous system and in cardiac tissue, indicating that these tissues may be involved in the biosynthesis of steroid hormones acting in an autocrine or paracrine manner. This review presents a detailed description of the enzymes involved in the biosynthesis of active steroid hormones, with emphasis on the human and mouse enzymes and their expression in gonads, adrenal glands, and placenta.
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Affiliation(s)
- Anita H Payne
- Division of Reproductive Biology, Department of Obstetrics and Gynecology, Stanford University School of Medicine, 300 Pasteur Drive, Stanford, California 94305-5317, USA.
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Yu H, Cheng H, Guo Y, Xia L, Zhou R. Alternative splicing and differential expression of P450c17 (CYP17) in gonads during sex transformation in the rice field eel. Biochem Biophys Res Commun 2003; 307:165-71. [PMID: 12849996 DOI: 10.1016/s0006-291x(03)01137-9] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Several mechanisms were used in determination of the development of the male or female of vertebrates. The genes for determination of sequential hermaphrodite sex are unknown. Here, we reported cloning, alternative splicing, and expression patterns of the CYP17 gene of the rice field eel, a teleost fish with a characteristic of nature sex reversal. The CYP17 gene of the rice field eel was clustered into the CYP17 gene group of all the other vertebrates, especially into the fish subgroup. Four isoforms of the CYP17 were generated in gonads by alternative splicing and polyadenylation. Alternative splicing events of all these isoforms occurred in 3(') regions, which encoded three different sizes (517, 512, and 159aa) of proteins. RT-PCR results indicate specific expression in gonads of these isoforms. Northern blot analysis shows that expression patterns of the CYP17 (dominantly expressed in testis, less in ovary, and the least in ovotestis) are consistent with the sex reversal process of the rice field eel. In situ hybridization further shows its specific expression in germinal lamellae, the gonadal epithelium of the gonads. These findings indicate that CYP17 is differentially regulated in a sex- and developmentally specific manner, suggesting that the CYP17 potentially has important roles in gonad differentiation during sex reversal of the rice field eel.
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Affiliation(s)
- Hongshi Yu
- Molecular and Developmental Genetics Laboratory, Department of Genetics and Center for Developmental Biology, College of Life Sciences, Wuhan University, Wuhan, 430072, PR China
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Swart AC, Kolar NW, Lombard N, Mason JI, Swart P. Baboon cytochrome P450 17alpha-hydroxylase/17,20-lyase (CYP17). EUROPEAN JOURNAL OF BIOCHEMISTRY 2002; 269:5608-16. [PMID: 12423360 DOI: 10.1046/j.1432-1033.2002.03268.x] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Human cytochrome P450 17alpha-hydroxylase (CYP17) catalyses not only the 17alpha-hydroxlation of pregnenolone and progesterone and the C17,20-side chain cleavage (lyase) of 17alpha-hydroxypregnenolone, necessary for the biosynthesis of C21-glucocorticoids and C19-androgens, but also catalyses the 16alpha-hydroxylation of progesterone. In efforts to understand the complex enzymology of CYP17, structure/function relationships have been reported previously after expressing recombinant DNAs, encoding CYP17 from various species, in nonsteroidogenic mammalian or yeast cells. A major difference between species resides in the lyase activity towards the hydroxylated intermediates and in the fact that the secretion of C19-steroids take place, in some species, principally in the gonads. Because human and higher primate adrenals secrete steroids, CYP17 has been characterized in the Cape baboon, a species more closely related to humans, in an effort to gain a further understanding of the reactions catalysed by CYP17. Baboon and human CYP17 cDNA share 96% homology. Baboon CYP17 has apparent Km and V values for pregnenolone and progesterone of 0.9 micro m and 0.4 nmol.h-1.mg protein-1 and 6.5 micro m and 3.9 nmol.h-1.mg protein-1, respectively. Baboon CYP17 had a significantly higher activity for progesterone hydroxylation relative to pregnenolone. No 16alpha-hydroxylase and no lyase activity for 17alpha-hydroxyprogesterone. Sequence analyses showed that there are 28 different amino acid residues between human and baboon CYP17, primarily in helices F and G and the F-G loop.
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Affiliation(s)
- Amanda C Swart
- Department of Biochemistry, University of Stellenbosch, South Africa; Department of Reproductive & Developmental Sciences, University of Edinburgh Medical School, Scotland, UK.
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Veldhuis JD, Zhang G, Garmey JC. Troglitazone, an insulin-sensitizing thiazolidinedione, represses combined stimulation by LH and insulin of de novo androgen biosynthesis by thecal cells in vitro. J Clin Endocrinol Metab 2002; 87:1129-33. [PMID: 11889176 DOI: 10.1210/jcem.87.3.8308] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/12/2023]
Abstract
Polycystic ovarian syndrome (anovulatory hyperandrogenism) is marked by adolescent onset of systemic hyperinsulinism, oligoovulation, hirsutism, excessive LH and androgen secretion, and variable reduction in fertility. Insulin and LH are believed to act in concert to promote ovarian androgen hypersecretion in this disorder. Administration of troglitazone, an insulin-sensitizing agent and putative PPAR gamma agonist, can decrease hyperinsulinism, suppress T production, and ameliorate oligoovulation in some women with this endocrinopathy. The present study tests the hypothesis that troglitazone directly inhibits de novo androgen biosynthesis stimulated jointly by LH and insulin in primary cultures of (porcine) thecal cells. We show that troglitazone dose-dependently antagonizes LH/insulin's combined stimulation of androstenedione and T production by thecal cells in vitro. Consistent steroidogenic inhibition of 80-95% was achieved at drug concentrations of 3-6.8 microM (P < 0.001). Exposure of thecal cells to the thiazolidinedione derivative also blocked bihormonally stimulated accumulation of CYP17 (cytochrome P450 17 alpha-hydroxylase/C(17-20) lyase) gene expression, as reflected by decreased accumulation of cognate heterogeneous nuclear RNA and mRNA (by 30-65%; P < 0.05). Moreover, troglitazone suppressed LH/insulin-induced phosphorylation of the 52-kDa immunoprecipitated CYP17 enzyme by 88% (P < 0.001). A putative natural agonist of PPAR gamma nuclear transcription, 15-deoxy-delta-12,14-prostaglandin J(2), also inhibited LH/insulin-driven androstenedione biosynthesis and CYP17 gene expression in thecal cells. In conclusion, a synthetic thiazolidinedione (troglitazone) and a natural ligand of PPAR gamma (15-deoxy-delta-12,14-prostaglandin J(2)) effectively impede the concerted stimulation by LH and insulin of in vitro thecal cell androgen production, CYP17 gene expression, and CYP17 protein phosphorylation. This ensemble of inhibitory actions on LH/insulin-stimulated steroidogenesis offers a plausible mechanistic basis for at least part of the observed clinical efficacy of troglitazone in mitigating androgen excess in women with polycystic ovarian syndrome.
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Affiliation(s)
- Johannes D Veldhuis
- Division of Endocrinology, Department of Internal Medicine, National Institutes of Health Specialized Cooperative Center in Reproductive Research, University of Virginia School of Medicine, Charlottesville, Virginia 22908, USA.
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Brock BJ, Waterman MR. The use of random chimeragenesis to study structure/function properties of rat and human P450c17. Arch Biochem Biophys 2000; 373:401-8. [PMID: 10620365 DOI: 10.1006/abbi.1999.1557] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The microsomal 17alpha-hydroxylase/17,20-lyase cytochrome P450 (P450c17) catalyzes the 17alpha-hydroxylase reaction required to produce cortisol, the major glucocorticoid in many species and the 17,20-lyase activity required for the production of androgens in all species. Utilizing the technique of random chimeragenesis we have attempted to map regions of primary sequence that contribute to the species-specific biochemical differences between rat and human P450c17. We have previously reported significant differences between rat and human P450c17 in their activities, stability and substrate-dependent coupling efficiencies even though they share 68% amino acid identity. Identification of the regions of primary sequence that contribute to each of these properties would be helpful in understanding the structure/function relationships in this enzyme. A single plasmid containing the cDNAs encoding both enzymes in a tandem orientation was constructed. This plasmid was linearized at unique restriction sites and used to transform Escherichia coli. A three-step screening protocol identified five chimeras with a uniform distribution of 5' rat and 3' human sequence. All chimeric proteins yield the characteristic reduced-CO difference spectra, indicating proper folding. The chimeras exhibit a range of stability and activities that are not consistent with the degree of parental primary sequence. A chimera containing 301 N-terminal rat P450c17 amino acids and lacking the rat P450c17 phenylalanine 343, had the highest lyase activity. Generation of these functional rat/human chimeras suggests that the tertiary structures of rat and human P450c17 are sufficiently conserved to allow proper folding of chimeric enzymes. However, the properties of these chimeras did not permit identification of a region of primary sequence that contributes to a species-specific property of rat and human P450c17. Stability of these chimeras and insight into the presence of secondary structural elements is discussed.
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Affiliation(s)
- B J Brock
- Department of Biochemistry, Vanderbilt University School of Medicine, 607 Light Hall, 23rd and Pierce Avenue, Nashville, Tennessee 37232-0146, USA
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HASEGAWA T, SATO F, ISHIDA N. Genomic Organization in the Amino Acid Coding Sequence of Equine CYP17 Gene. J Equine Sci 2000. [DOI: 10.1294/jes.11.99] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022] Open
Affiliation(s)
- Telhisa HASEGAWA
- Laboratory of Molecular and Cellular Biology, Equine Research Institute
| | - Fumio SATO
- Laboratory of Molecular and Cellular Biology, Equine Research Institute
| | - Nobushige ISHIDA
- Laboratory of Molecular and Cellular Biology, Equine Research Institute
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Borroni R, Liu Z, Simpson ER, Hinshelwood MM. A putative binding site for Sp1 is involved in transcriptional regulation of CYP17 gene expression in bovine ovary. Endocrinology 1997; 138:2011-20. [PMID: 9112400 DOI: 10.1210/endo.138.5.5112] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
In the bovine ovary, thecal cells are the only cell type capable of expressing the CYP17 gene in response to LH. With the onset of ovulation and luteinization in the cow, there is complete loss of P450c17alpha expression. To characterize the molecular mechanisms involved in tissue-specific regulation of the CYP17 gene in the bovine ovary, deletion mutations of the bovine CYP17 promoter were ligated into a promoterless luciferase expression vector, and reporter constructs were transiently transfected into primary cultures of bovine thecal and luteal cells. Deletion of the promoter sequences between -191 and 101 bp dramatically decreased the levels of reporter gene activity in both thecal and luteal cells. Computer-assisted analysis revealed the presence of a putative inverted Sp1-like binding site at -188/-180 bp. Deletion or mutation of this sequence caused a decrease in both basal and forskolin-stimulated reporter gene activity. In addition, mutation or deletion of this sequence also decreased reporter gene expression induced by overexpression of the protein kinase A catalytic subunit. Electrophoretic mobility shift assays showed that this sequence binds to a nuclear protein(s) from both thecal and luteal cells that is related to Sp1, as suggested by the results of gel mobility supershift assay employing an antibody raised against Sp1. DNA-binding activity was not increased by the addition of forskolin to thecal or luteal cells. We conclude that this inverted Sp1-like binding sequence is involved in constitutive as well as cAMP-dependent expression of the CYP17 gene in the bovine ovary.
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Affiliation(s)
- R Borroni
- Department of Obstetrics/Gynecology, University of Texas Southwestern Medical Center, Dallas 75235-9051, USA
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Zhang P, Han XG, Mellon SH, Hall PF. Expression of the gene for cytochrome P-450 17α-hydroxylase/C17–20 lyse (CYP17) in porcine Leydig cells: identification of a DNA sequence that mediates cAMP response. ACTA ACUST UNITED AC 1996. [DOI: 10.1016/0167-4781(96)00016-4] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Givens CR, Zhang P, Bair SR, Mellon SH. Transcriptional regulation of rat cytochrome P450c17 expression in mouse Leydig MA-10 and adrenal Y-1 cells: identification of a single protein that mediates both basal and cAMP-induced activities. DNA Cell Biol 1994; 13:1087-98. [PMID: 7702752 DOI: 10.1089/dna.1994.13.1087] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Cytochrome P450c17, 17 alpha-hydroxylase/17,20 lyase, is a key enzyme in the steroidogenic pathway leading to the production of corticosteroids and androgens from the adrenal gland and sex steroids from the gonads. Both enzymatic activities of the protein are encoded by a single gene, CYP17, which is expressed in both the human adrenal and gonad but not in the placenta, and in the rodent gonad and placenta but not the rodent adrenal. We isolated and sequenced a full-length rat genomic clone (7,553 bases) containing the entire coding region of the rat P450c17 gene, and all intronic sequences and 1,560 bp of 5'-flanking DNA (EMBL Acc#X69816). To determine which sequences in the rat P450c17 promoter may be responsible for basal and cAMP-stimulated gene transcription, deletion constructs containing between -1,560 and -53 base pairs of 5'-flanking DNA from the rat P450c17 gene were ligated to plasmids expressing the reporter gene luciferase and transfected into two mouse cell lines, adrenal Y-1 cells, and testicular Leydig MA-10 cells. Highest basal and cAMP-stimulated luciferase activity were found in constructions containing 156 bp of 5'-flanking DNA. This construction contains a sequence very similar to the consensus cis element reported to be responsible for cAMP enhancement of the rat somatostatin gene and also overlaps a sequence similar to the consensus element for the orphan steroid receptor SF-1. Gel mobility-shift analysis, using a 30-bp oligonucleotide containing this region incubated with cellular extracts from cultured mouse adrenal Y-1 and mouse Leydig MA-10 cells, revealed all the extracts to contain two proteins that bind to this sequence. Neither DNA-protein complex was further retarded by co-incubation with an anti-CREB antibody, suggesting that cAMP regulation of this gene occurs via a non-CREB protein. Mutation of this oligonucleotide resulted in loss of binding of only one of these proteins, but resulted in loss of both basal and cAMP stimulation of rat P450c17 promoter-regulated gene transcription. Southwestern analysis suggests that one of these proteins is larger than SF-1. This study suggests that a protein that binds to an SF-1 like sequence regulates both basal and cAMP-stimulated rat P450c17 gene expression in rodent cells.
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Affiliation(s)
- C R Givens
- Department of Obstetrics, Gynecology and Reproductive Sciences, University of California, San Francisco 94143-0556, USA
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Kim YH, Yoo HY, Jung G, Kim JY, Rho HM. Isolation and analysis of the rat genomic sequence encoding Cu/Zn superoxide dismutase. Gene 1993; 133:267-71. [PMID: 8224914 DOI: 10.1016/0378-1119(93)90650-r] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
A rat genomic DNA (SOD1) encoding Cu/Zn superoxide dismutase (SOD1) (superoxide; superoxide oxidoreductase, EC 1.15.1.1) was cloned and sequenced. The rat SOD1 gene consisted of five exons and four introns spanning about 6 kb. The transcription start point (tsp) was observed 93 bp upstream from the ATG codon by primer extension analysis. The 5'-flanking sequence of SOD1 contained two CCAAT box motifs, a TATA box and four GC-like boxes. In the 3'-flanking region of SOD1, a polyadenylation signal, consensus sequence YGTGTTYY, and a G/T cluster were observed. A rat identifier (ID) sequence, a repetitive element of the rat genome, was located at between 569 and 484 bp upstream from the tsp.
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Affiliation(s)
- Y H Kim
- Department of Molecular Biology, Seoul National University, South Korea
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Fevold HR, Ivanovitch JD, Zanger UM, Waterman MR. The sequence of the 5'-end of the rat CYP17 gene, the transcription initiation site and a comparison with the homologous genes of other species. Mol Cell Endocrinol 1993; 95:95-100. [PMID: 8243812 DOI: 10.1016/0303-7207(93)90033-g] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
A clone bearing the rat CYP17 gene has been isolated and the sequence determined for 417 nucleotides 5' to the translation start site. The sequence shows one difference, a G-C inversion, with that published by Zhang et al. (1992). A transcription initiation site has been located at position -41 relative to the translation start site; this confirms the location published by Nason et al. (1992) with the caveat of the G-C inversion, so that the transcription start site becomes G instead of C. Overall percent similarities of this sequence with those of bovine, human, pig and mouse show values of 58, 64, 65, and 82, respectively. Similar comparisons done for the cAMP-responsive sequences, CRS-1 and CRS-2 (Lund et al., 1990), show 42, 55, 47 and 95% similarities for CRS-1, and 56, 77, 71 and 90% for CRS-2. These comparisons suggest that the highly conserved rat and mouse gene sequences corresponding to the bovine CRS-1 and CRS-2 may be important for either negative regulation of this gene in the adrenal or positive regulation in the gonads of these two species.
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Affiliation(s)
- H R Fevold
- Division of Biological Sciences, University of Montana, Missoula 59812
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Nelson DR, Kamataki T, Waxman DJ, Guengerich FP, Estabrook RW, Feyereisen R, Gonzalez FJ, Coon MJ, Gunsalus IC, Gotoh O. The P450 superfamily: update on new sequences, gene mapping, accession numbers, early trivial names of enzymes, and nomenclature. DNA Cell Biol 1993; 12:1-51. [PMID: 7678494 DOI: 10.1089/dna.1993.12.1] [Citation(s) in RCA: 1077] [Impact Index Per Article: 34.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
We provide here a list of 221 P450 genes and 12 putative pseudogenes that have been characterized as of December 14, 1992. These genes have been described in 31 eukaryotes (including 11 mammalian and 3 plant species) and 11 prokaryotes. Of 36 gene families so far described, 12 families exist in all mammals examined to date. These 12 families comprise 22 mammalian subfamilies, of which 17 and 15 have been mapped in the human and mouse genome, respectively. To date, each subfamily appears to represent a cluster of tightly linked genes. This revision supersedes the previous updates [Nebert et al., DNA 6, 1-11, 1987; Nebert et al., DNA 8, 1-13, 1989; Nebert et al., DNA Cell Biol. 10, 1-14 (1991)] in which a nomenclature system, based on divergent evolution of the superfamily, has been described. For the gene and cDNA, we recommend that the italicized root symbol "CYP" for human ("Cyp" for mouse), representing "cytochrome P450," be followed by an Arabic number denoting the family, a letter designating the subfamily (when two or more exist), and an Arabic numeral representing the individual gene within the subfamily. A hyphen should precede the final number in mouse genes. "P" ("p" in mouse) after the gene number denotes a pseudogene. If a gene is the sole member of a family, the subfamily letter and gene number need not be included. We suggest that the human nomenclature system be used for all species other than mouse. The mRNA and enzyme in all species (including mouse) should include all capital letters, without italics or hyphens. This nomenclature system is identical to that proposed in our 1991 update. Also included in this update is a listing of available data base accession numbers for P450 DNA and protein sequences. We also discuss the likelihood that this ancient gene superfamily has existed for more than 3.5 billion years, and that the rate of P450 gene evolution appears to be quite nonlinear. Finally, we describe P450 genes that have been detected by expressed sequence tags (ESTs), as well as the relationship between the P450 and the nitric oxide synthase gene superfamilies, as a likely example of convergent evolution.
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Affiliation(s)
- D R Nelson
- Department of Biochemistry and Biophysics, University of North Carolina, Chapel Hill 27599
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