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Lai X, Peng S, Liu L, Zou Z, Cao L, Wang Y. Tissue-specific promoters regulate the transcription of cyp19a1 in the brain-pituitary-gonad axis of Japanese eel (Anguilla japonica). J Steroid Biochem Mol Biol 2023; 232:106334. [PMID: 37236374 DOI: 10.1016/j.jsbmb.2023.106334] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/13/2023] [Revised: 05/16/2023] [Accepted: 05/22/2023] [Indexed: 05/28/2023]
Abstract
Aromatase is a key enzyme that catalyzes the biosynthesis of estrogens. Previous study indicated that putative tissue-specific promoters of the one aromatase gene (cyp19a1) may drive the differential regulatory mechanisms of cyp19a1 expression in Anguilla japonica. In the present study, for elucidating the transcription characteristics and the function of putative tissue-specific promoters of cyp19a1 in the brain-pituitary-gonad (BPG) axis during vitellogenesis, we investigated the transcriptional regulation of cyp19a1 by 17β-estrogen (E2), testosterone (T), or human chorionic gonadotropin (HCG) in A. japonica. The expression of estrogen receptor (esra), androgen receptor (ara), or luteinizing hormone receptor (lhr) was up-regulated as cyp19a1 in response to E2, T, or HCG, respectively in the telencephalon, diencephalon, and pituitary. The expression of cyp19a1 was also upregulated in the ovary by HCG or T in a dose-dependent manner. Unlike in the brain and pituitary, the expression of esra and lhr, rather than ara, was upregulated by T in the ovary. Subsequently, four primary subtypes of 5'-untranslated terminal regions of cyp19a1 transcripts and the corresponding two 5' flanking regions (promoter P.I and P.II) were identified. The P.II existed in all BPG axis tissues, whereas the P.I with strong transcriptional activity was brain- and pituitary-specific. Furthermore, the transcriptional activity of promoters, the core promoter region, and the three putative hormone receptor response elements were validated. The transcriptional activity did not change when the HEK291T cells co-transfected with P.II and ar vector were exposed to T. These results suggested that the expression of cyp19a1 was upregulated indirectly through esra and lhr rather than ara by T in the ovary, whereas the expression of cyp19a1 was upregulated directly through androgen receptor and the downstream androgen response element of tissue-specific P.I in the brain and pituitary. The results of the study reveal the regulatory mechanisms of estrogen biosynthesis and provide a reference for optimizing the technology of artificially induced maturation in eels.
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Affiliation(s)
- Xiaojian Lai
- Fisheries College, Jimei University, Xiamen 361021, China; Engineering Research Center of the Modern Technology for Eel Industry, Ministry of Education P. R. China, Xiamen 361021, China.
| | - Shuai Peng
- Fisheries College, Jimei University, Xiamen 361021, China
| | - Liping Liu
- College of Fisheries and Life Science, Shanghai Ocean University, Shanghai 201306, China
| | - Zhihua Zou
- Fisheries College, Jimei University, Xiamen 361021, China
| | - Le Cao
- Fisheries College, Jimei University, Xiamen 361021, China; Engineering Research Center of the Modern Technology for Eel Industry, Ministry of Education P. R. China, Xiamen 361021, China
| | - Yilei Wang
- Fisheries College, Jimei University, Xiamen 361021, China.
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Thompson RR, Mangiamele LA. Rapid sex steroid effects on reproductive responses in male goldfish: Sensory and motor mechanisms. Horm Behav 2018; 104:52-62. [PMID: 29777656 DOI: 10.1016/j.yhbeh.2018.05.007] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/06/2018] [Revised: 05/06/2018] [Accepted: 05/08/2018] [Indexed: 12/27/2022]
Abstract
Contribution to Special Issue on Fast effects of steroids. Although we have learned a great deal about the molecular mechanisms through which sex steroids rapidly affect cellular physiology, we still know little about the links between those mechanisms and behavioral output, nor about their functional consequences in natural contexts. In this review, we first briefly discuss the contexts associated with rapid effects of sex steroids on reproductive behaviors and their likely functional outcomes, as well the sensory, motor, and motivational mechanisms associated with those effects. We then discuss our recent studies on the rapid effects of testosterone in goldfish. Those studies indicate that testosterone, through its aromatization and the subsequent activation of estrogen receptors, rapidly stimulates physiological processes related to the release of milt/sperm through likely influences on motor pathways, as well as behavioral responses to female visual stimuli that may reflect, in part, influences on early stages of sensory processing. Such motor and sensory mechanism are likely important for sperm competition and mate detection / tracking, respectively, in competitive mating contexts. We also present preliminary data on rapid effects of testosterone on responses to pheromones that may not involve estrogen receptors, suggesting a dissociation in the receptor mechanisms that mediate behavioral responses in different sensory modalities. Lastly, we briefly discuss the implications of our work on unresolved questions about rapid sex steroid neuromodulation in fish.
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Affiliation(s)
- Richmond R Thompson
- Department of Psychology, Program in Neuroscience, Bowdoin College, Brunswick, ME 04011, United States.
| | - Lisa A Mangiamele
- Department of Biological Sciences, Smith College, North Hampton, MA 01063, United States
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Orrego R, Milestone CB, Hewitt LM, Guchardi J, Heid-Furley T, Slade A, MacLatchy DL, Holdway D. Evaluating the potential of effluent extracts from pulp and paper mills in Canada, Brazil, and New Zealand to affect fish reproduction: Estrogenic effects in fish. ENVIRONMENTAL TOXICOLOGY AND CHEMISTRY 2017; 36:1547-1555. [PMID: 27808443 DOI: 10.1002/etc.3675] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/07/2016] [Revised: 07/26/2016] [Accepted: 11/01/2016] [Indexed: 05/24/2023]
Abstract
The authors examined the potential of pulp mill effluent from pulp-producing countries (Canada, Brazil, New Zealand) to affect fish reproduction. Specifically, the estrogenic effects in juvenile rainbow trout (Oncorhynchus mykiss) pulse-exposed to 11 different mill effluent extracts (intraperitoneal injections of solid-phase extraction-dichloromethane nonpolar fraction). The results indicated that effluent extracts were estrogenic in juvenile trout irrespective of the gender, as reflected by increasing level of plasma vitellogenin (VTG; Brazil > New Zealand > Canada). Despite the high variability observed among mills, differences in VTG levels were related to the type of mill process (kraft > elementary chlorine-free kraft > thermomechanical pulping). Moreover, effluent treatments did not appear to significantly decrease VTG induction. A consistent estrogenic effect was observed in those mills that process a combination of feedstocks (softwood and hardwood), with the highest increase in VTG related to eucalyptus feedstock. The results demonstrate significant estrogenic effects of pulp mill effluents on chronically exposed juvenile trout, suggesting that in vivo metabolic activation of precursors is necessary to cause the observed increases in VTG levels. This molecular estrogenic response provides a useful starting point for predicting population-level impacts through the adverse outcome pathway methodology. Environ Toxicol Chem 2017;36:1547-1555. © 2016 SETAC.
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Affiliation(s)
- Rodrigo Orrego
- Faculty of Marine Sciences and Biological Resources, Natural Science Institute Alexander von Humboldt, University of Antofagasta, Antofagasta, Chile
- Faculty of Science, University of Ontario Institute of Technology, Oshawa, Ontario, Canada
| | - Craig B Milestone
- Aquatic Ecosystem Protection Research Division, Environment and Climate Change Canada, Burlington, Ontario, Canada
| | - L Mark Hewitt
- Aquatic Ecosystem Protection Research Division, Environment and Climate Change Canada, Burlington, Ontario, Canada
| | - John Guchardi
- Faculty of Science, University of Ontario Institute of Technology, Oshawa, Ontario, Canada
| | | | | | | | - Douglas Holdway
- Faculty of Science, University of Ontario Institute of Technology, Oshawa, Ontario, Canada
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Morton T, Wong WK, Megraw M. TIPR: transcription initiation pattern recognition on a genome scale. Bioinformatics 2015; 31:3725-32. [PMID: 26254489 DOI: 10.1093/bioinformatics/btv464] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2014] [Accepted: 08/03/2015] [Indexed: 12/15/2022] Open
Abstract
MOTIVATION The computational identification of gene transcription start sites (TSSs) can provide insights into the regulation and function of genes without performing expensive experiments, particularly in organisms with incomplete annotations. High-resolution general-purpose TSS prediction remains a challenging problem, with little recent progress on the identification and differentiation of TSSs which are arranged in different spatial patterns along the chromosome. RESULTS In this work, we present the Transcription Initiation Pattern Recognizer (TIPR), a sequence-based machine learning model that identifies TSSs with high accuracy and resolution for multiple spatial distribution patterns along the genome, including broadly distributed TSS patterns that have previously been difficult to characterize. TIPR predicts not only the locations of TSSs but also the expected spatial initiation pattern each TSS will form along the chromosome-a novel capability for TSS prediction algorithms. As spatial initiation patterns are associated with spatiotemporal expression patterns and gene function, this capability has the potential to improve gene annotations and our understanding of the regulation of transcription initiation. The high nucleotide resolution of this model locates TSSs within 10 nucleotides or less on average. AVAILABILITY AND IMPLEMENTATION Model source code is made available online at http://megraw.cgrb.oregonstate.edu/software/TIPR/. CONTACT megrawm@science.oregonstate.edu. SUPPLEMENTARY INFORMATION Supplementary data are available at Bioinformatics online.
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Affiliation(s)
- Taj Morton
- Department of Electrical Engineering and Computer Science, Oregon State University, Corvallis, OR 97331, USA
| | - Weng-Keen Wong
- Department of Electrical Engineering and Computer Science, Oregon State University, Corvallis, OR 97331, USA
| | - Molly Megraw
- Department of Electrical Engineering and Computer Science, Oregon State University, Corvallis, OR 97331, USA, Department of Botany and Plant Pathology, Oregon State University, Corvallis, OR 97331, USA and Center for Genome Research and Biocomputing, Oregon State University, Corvallis, OR 97331, USA
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Zhang Y, Zhang S, Lu H, Zhang L, Zhang W. Genes encoding aromatases in teleosts: evolution and expression regulation. Gen Comp Endocrinol 2014; 205:151-8. [PMID: 24859258 DOI: 10.1016/j.ygcen.2014.05.008] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/11/2013] [Revised: 04/29/2014] [Accepted: 05/07/2014] [Indexed: 11/17/2022]
Abstract
Cytochrome P450 aromatases, encoded by cyp19a1 genes, catalyzes the conversion of androgens to estrogens and plays important roles in the reproduction of vertebrates. Vertebrate cyp19a1 genes showed high synteny in chromosomal locations and conservation in sequences during evolution. However, amphioxus cyp19a1 does not show synteny to vertebrate cyp19a1. Teleost fish possess two copies of the cyp19a1 gene, which were postulated to result from a fish-specific genome duplication. The duplicated copies of fish cyp19a1 genes evolved into the brain and ovarian forms of cytochrome P450 aromatase genes, cyp19a1a and cyp19a1b, respectively, with different regulatory mechanisms of expression, through subfunctionalization under long-term selective pressure. In addition to the estradiol (E2) auto-regulatory loop, there may be other mechanisms responsible for the high expression of aromatase in the teleost brain. The study of the two cyp19a1 copies in teleost fish will shed light on the general evolution, function, and regulation of vertebrate cyp19a1.
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Affiliation(s)
- Yang Zhang
- School of Life Sciences, Sun Yat-sen University, Guangzhou 510275, PR China
| | - Shen Zhang
- School of Life Sciences, Sun Yat-sen University, Guangzhou 510275, PR China
| | - Huijie Lu
- School of Life Sciences, Sun Yat-sen University, Guangzhou 510275, PR China
| | - Lihong Zhang
- School of Life Sciences, Sun Yat-sen University, Guangzhou 510275, PR China.
| | - Weimin Zhang
- School of Life Sciences, Sun Yat-sen University, Guangzhou 510275, PR China.
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Remage-Healey L. Brain estrogen signaling effects acute modulation of acoustic communication behaviors: A working hypothesis. Bioessays 2012; 34:1009-16. [PMID: 23065844 DOI: 10.1002/bies.201200081] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Although estrogens are widely considered circulating "sex steroid hormones" typically associated with female reproduction, recent evidence suggests that estrogens can act as local modulators of brain circuits in both males and females. The functional implications of this newly characterized estrogen signaling system have begun to emerge. This essay summarizes evidence in support of the hypothesis that the rapid production of estrogens in brain circuits can drive acute changes in both the production and perception of acoustic communication behaviors. These studies have revealed two fundamental neurobiological concepts: (1) estrogens can be locally produced in brain circuits, independent of levels in nearby circuits and in the circulation and (2) estrogens can have very rapid effects within these brain circuits to modulate social vocalizations, acoustic processing, and sensorimotor integration. This vertebrate-wide span of research, including vocalizing fishes, amphibians, and birds, emphasizes the importance of comparative model systems in understanding principles of neurobiology.
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Affiliation(s)
- Luke Remage-Healey
- Neuroscience and Behavior Program, Center for Neuroendocrine Studies, University of Massachusetts, Amherst, MA, USA.
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Zhang Y, Zhang S, Zhou W, Ye X, Ge W, Cheng CHK, Lin H, Zhang W, Zhang L. Androgen rather than estrogen up-regulates brain-type cytochrome P450 aromatase (cyp19a1b) gene via tissue-specific promoters in the hermaphrodite teleost ricefield eel Monopterus albus. Mol Cell Endocrinol 2012; 350:125-35. [PMID: 22178793 DOI: 10.1016/j.mce.2011.12.001] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/14/2011] [Revised: 12/01/2011] [Accepted: 12/02/2011] [Indexed: 11/30/2022]
Abstract
CYP19A1 in the brain and pituitary of vertebrates is important for reproductive and non-reproductive processes. In teleosts, it is broadly accepted that estradiol (E(2)) up-regulates cyp19a1b gene via a positive autoregulatory loop. Our present study, however, showed that E(2) did not up-regulate ricefield eel cyp19a1b in the hypothalamus and pituitary, whereas dihydrotestosterone (DHT) or testosterone (T) stimulated cyp19a1b expression only in the pituitary. Two tissue-specific promoters, namely promoter I and II directing the expression in the brain and pituitary respectively, were identified. Promoter I contained a non-consensus estrogen response element (ERE), and consequently did not respond to E(2). Promoter II contained an androgen response element (ARE) and consequently responded to DHT. Taken together, these results demonstrated a novel steroidal regulation of cyp19a1b gene expression and an alternative usage of tissue-specific cyp19a1b promoters in the brain and pituitary of a teleost species, the ricefield eel.
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Affiliation(s)
- Yang Zhang
- Department of Biology, School of Life Sciences, Sun Yat-Sen University, Guangzhou 510275, PR China
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Zhang W, Lu H, Jiang H, Li M, Zhang S, Liu Q, Zhang L. Isolation and characterization of cyp19a1a and cyp19a1b promoters in the protogynous hermaphrodite orange-spotted grouper (Epinephelus coioides). Gen Comp Endocrinol 2012; 175:473-87. [PMID: 22197207 DOI: 10.1016/j.ygcen.2011.12.005] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/30/2011] [Revised: 11/20/2011] [Accepted: 12/02/2011] [Indexed: 11/25/2022]
Abstract
Aromatase (CYP19A1) catalyzes the conversion of androgens to estrogens. In teleosts, duplicated copies of cyp19a1 genes, namely cyp19a1a and cyp19a1b, were identified, however, the transcriptional regulation of these two genes remains poorly understood. In the present study, the 5'-flanking regions of the orange-spotted grouper cyp19a1a (gcyp19a1a) and cyp19a1b (gcyp19a1b) genes were isolated and characterized. The proximal promoter regions of both genes were relatively conserved when compared to those of the other teleosts. Notably, a conserved FOXO transcriptional factor binding site was firstly reported in the proximal promoter of gcyp19a1a, and deletion of the region (-112 to -60) containing this site significantly decreased the promoter activities. The deletion of the region (-246 to -112) containing the two conserved FTZ-F1 sites also dramatically decreased the transcriptional activities of gcyp19a1a promoter, and both two FTZ-F1 sites were shown to be stimulatory cis-acting elements. A FTZ-F1 homologue isolated from ricefield eel (eFTZ-F1) up-regulated gcyp19a1a promoter activities possibly via the FTZ-F1 sites, however, a previously identified orange-spotted grouper FTZ-F1 homologue (gFTZ-F1) did not activate the transcription of gcyp19a1a promoter unexpectedly. As to gcyp19a1b promoter, all the deletion constructs did not show good promoter activities in either TM4 or U251-MG cells. Estradiol (100nM) up-regulated gcyp19a1b promoter activities by about 13- and 36-fold in TM4 and U251-MG cells, respectively, via the conserved ERE motif, but did not stimulate gcyp19a1a promoter activities. These results are helpful to further elucidate the regulatory mechanisms of cyp19a1a and cyp19a1b expression in the orange-spotted grouper as well as other teleosts.
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Affiliation(s)
- Weimin Zhang
- School of Life Sciences, Sun Yat-Sen University, Guanghzhou 510275, PR China.
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Marquez EC, Traylor-Knowles N, Novillo-Villajos A, Callard IP. Cloning of estrogen receptor alpha and aromatase cDNAs and gene expression in turtles (Chrysemys picta and Pseudemys scripta) exposed to different environments. Comp Biochem Physiol C Toxicol Pharmacol 2011; 154:213-25. [PMID: 21664488 DOI: 10.1016/j.cbpc.2011.05.008] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/26/2011] [Revised: 05/19/2011] [Accepted: 05/25/2011] [Indexed: 11/22/2022]
Abstract
Reproductive changes have been observed in painted turtles (Chrysemys picta) from a site with known contamination located on Cape Cod, MA, USA. We hypothesize that these changes are caused by exposure to endocrine-disrupting compounds and that genes playing a significant role in reproduction are affected. cDNA sequences were determined for estrogen receptor alpha and aromatase in the painted turtle. These genes were measured in our study animals using quantitative PCR. Adult turtles were trapped from our study site (Moody Pond, MP) or a reference site (Washburn Pond) and exposed to laboratory environments containing soil from either site. The red-eared slider (Pseudemys scripta), a pond turtle closely related to the painted turtle, was used to assess neonatal exposure to soil and water from the sites. Our results show an increase in hepatic estrogen receptor, which suggests exposure to estrogenic contaminants. Female turtles from MP appear to have a long-term effect on hepatic ER. Other findings were apparent age-dependent differences in expression of aromatase and ER in the brains of neonate and year-old juvenile turtles. Phylogenetic analyses of the cDNA sequences further support the hypothesis that turtles are in a sister clade to birds and crocodilians.
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Affiliation(s)
- Emily C Marquez
- Boston University, Department of Biology, 5 Cummington St., Boston, MA 02215, USA
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von Schalburg KR, Yasuike M, Yazawa R, de Boer JG, Reid L, So S, Robb A, Rondeau EB, Phillips RB, Davidson WS, Koop BF. Regulation and expression of sexual differentiation factors in embryonic and extragonadal tissues of Atlantic salmon. BMC Genomics 2011; 12:31. [PMID: 21232142 PMCID: PMC3034696 DOI: 10.1186/1471-2164-12-31] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2010] [Accepted: 01/13/2011] [Indexed: 12/14/2022] Open
Abstract
Background The products of cyp19, dax, foxl2, mis, sf1 and sox9 have each been associated with sex-determining processes among vertebrates. We provide evidence for expression of these regulators very early in salmonid development and in tissues outside of the hypothalamic-pituitary-adrenal/gonadal (HPAG) axis. Although the function of these factors in sexual differentiation have been defined, their roles in early development before sexual fate decisions and in tissues beyond the brain or gonad are essentially unknown. Results Bacterial artificial chromosomes containing salmon dax1 and dax2, foxl2b and mis were isolated and the regulatory regions that control their expression were characterized. Transposon integrations are implicated in the shaping of the dax and foxl2 loci. Splice variants for cyp19b1 and mis in both embryonic and adult tissues were detected and characterized. We found that cyp19b1 transcripts are generated that contain 5'-untranslated regions of different lengths due to cryptic splicing of the 3'-end of intron 1. We also demonstrate that salmon mis transcripts can encode prodomain products that present different C-termini and terminate before translation of the MIS hormone. Regulatory differences in the expression of two distinct aromatases cyp19a and cyp19b1 are exerted, despite transcription of their transactivators (ie; dax1, foxl2, sf1) occurring much earlier during embryonic development. Conclusions We report the embryonic and extragonadal expression of dax, foxl2, mis and other differentiation factors that indicate that they have functions that are more general and not restricted to steroidogenesis and gonadogenesis. Spliced cyp19b1 and mis transcripts are generated that may provide regulatory controls for tissue- or development-specific activities. Selection of cyp19b1 transcripts may be regulated by DAX-1, FOXL2 and SF-1 complexes that bind motifs in intron 1, or by signals within exon 2 that recruit splicing factors, or both. The potential translation of proteins bearing only the N-terminal MIS prodomain may modulate the functions of other TGF β family members in different tissues. The expression patterns of dax1 early in salmon embryogenesis implicate its role as a lineage determination factor. Other roles for these factors during embryogenesis and outside the HPAG axis are discussed.
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Affiliation(s)
- Kristian R von Schalburg
- Department of Biology, Centre for Biomedical Research, University of Victoria, Victoria, British Columbia, Canada
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Orrego R, McMaster M, Van Der Kraak G, Holdway D. Effects of pulp and paper mill effluent extractives on aromatase CYP19a gene expression and sex steroid levels in juvenile triploid rainbow trout. AQUATIC TOXICOLOGY (AMSTERDAM, NETHERLANDS) 2010; 97:353-360. [PMID: 20129681 DOI: 10.1016/j.aquatox.2010.01.002] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/17/2009] [Revised: 12/18/2009] [Accepted: 01/05/2010] [Indexed: 05/28/2023]
Abstract
We evaluated plasma testosterone (T) and 17beta-estradiol (E2) levels and ovarian aromatase CYP19a gene expression following a single intraperitoneal injection of Chilean pulp and paper mill effluent extracts into juvenile triploid rainbow trout. Fish injected with untreated effluent extracts had increased plasma T after 4 days, while plasma E2 concentration was increased in fish injected with both primary and secondary treated effluent extracts at the same sampling period. Ovarian CYP19a gene expression as measured by qRT-PCR was significantly induced in fish injected with the untreated, primary and secondary treated pulp and paper mill effluent extracts. Similar induction of CYP19a expression was found in fish injected with the androgens androstenedione (ADD) and T. A Principal Component Analysis (PCA) was conducted in order to identify structure in relationships between all measured variables and identifying which factors were most responsible for the variance observed within the plasma steroid levels, upregulation of ovarian CYP19a gene expression and the final estrogenic effect of increased plasma VTG levels. This analysis indicated a cluster correlation between plasma T levels and CYP19a gene expression (Factor 1, explaining 27.2% of total variance), a cluster including condition factor and liver somatic index (Factor 2, explaining 17.3%) and an additional cluster including plasma E2 and vitellogenin levels (Factor 3, explaining an additional 15.8%). The present results indicate that Chilean pulp and paper mill effluent extracts cause estrogenic effects in triploid rainbow trout. These effects could be related to the compounds present in the effluent that act as estrogen receptor agonists, or that induce changes leading to increased amounts of endogenous estrogens, reflected by increased E2 levels and induced aromatase expression/activity.
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Affiliation(s)
- Rodrigo Orrego
- Faculty of Science, University of Ontario Institute of Technology, 2000 Simcoe Street North, Oshawa, ON, Canada L1H7K4.
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Diotel N, Le Page Y, Mouriec K, Tong SK, Pellegrini E, Vaillant C, Anglade I, Brion F, Pakdel F, Chung BC, Kah O. Aromatase in the brain of teleost fish: expression, regulation and putative functions. Front Neuroendocrinol 2010; 31:172-92. [PMID: 20116395 DOI: 10.1016/j.yfrne.2010.01.003] [Citation(s) in RCA: 230] [Impact Index Per Article: 16.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/20/2009] [Revised: 01/20/2010] [Accepted: 01/24/2010] [Indexed: 12/25/2022]
Abstract
Unlike that of mammals, the brain of teleost fish exhibits an intense aromatase activity due to the strong expression of one of two aromatase genes (aromatase A or cyp19a1a and aromatase B or cyp19a1b) that arose from a gene duplication event. In situ hybridization, immunohistochemistry and expression of GFP (green fluorescent protein) in transgenic tg(cyp19a1b-GFP) fish demonstrate that aromatase B is only expressed in radial glial cells (RGC) of adult fish. These cells persist throughout life and act as progenitors in the brain of both developing and adult fish. Although aromatase B-positive radial glial cells are most abundant in the preoptic area and the hypothalamus, they are observed throughout the entire central nervous system and spinal cord. In agreement with the fact that brain aromatase activity is correlated to sex steroid levels, the high expression of cyp19a1b is due to an auto-regulatory loop through which estrogens and aromatizable androgens up-regulate aromatase expression. This mechanism involves estrogen receptor binding on an estrogen response element located on the cyp19a1b promoter. Cell specificity is achieved by a mandatory cooperation between estrogen receptors and unidentified glial factors. Given the emerging roles of estrogens in neurogenesis, the unique feature of the adult fish brain suggests that, in addition to classical functions on brain sexual differentiation and sexual behaviour, aromatase expression in radial glial cells could be part of the mechanisms authorizing the maintenance of a high proliferative activity in the brain of fish.
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Affiliation(s)
- Nicolas Diotel
- Neurogenesis And OEstrogens, UMR CNRS 6026, IFR 140, Université de Rennes 1, Rennes, France
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von Schalburg KR, Yasuike M, Davidson WS, Koop BF. Regulation, expression and characterization of aromatase (cyp19b1) transcripts in ovary and testis of rainbow trout (Oncorhynchus mykiss). Comp Biochem Physiol B Biochem Mol Biol 2010; 155:118-25. [PMID: 19895900 DOI: 10.1016/j.cbpb.2009.10.015] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2009] [Revised: 10/17/2009] [Accepted: 10/20/2009] [Indexed: 10/20/2022]
Abstract
Cytochrome P450 aromatase is the key enzyme in the pathway that converts androgens to estrogens. The enzyme functions in the smooth endoplasmic reticulum in a complex with NADPH-cytochrome P450 reductase. In teleost fish, at least two separate loci, cyp19a and cyp19b, encode distinct aromatase isoforms. The activity of cyp19a and cyp19b are predominantly associated with the ovary and brain, respectively, although their expression is not confined solely to these tissues. We found that at least five cyp19b1 transcripts with different 5'-UTRs are generated in the ovary and testis of rainbow trout. Regulation for selection of these variants may be through signals present in exon 2 that recruit alternative splicing factors. Also, binding elements for FOXL2 and SF-1 located within the cyp19b1 intron 1 may influence formation of transcripts that contain the 3'-end of the intron. Another transcript devoid of the exon 2 methionine initiator codon may utilize other downstream in-frame start codons. Less developed stages of ovarian and testicular tissues express only the intron-containing transcripts whereas precocious and more mature gonads express all five cyp19b1 messages. The function of these different 5'-UTRs may be for regulation of cyp19b1 at particular developmental stages or to specify control in distinct gonadal cell-types.
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Gohin M, Bobe J, Chesnel F. Comparative transcriptomic analysis of follicle-enclosed oocyte maturational and developmental competence acquisition in two non-mammalian vertebrates. BMC Genomics 2010; 11:18. [PMID: 20059772 PMCID: PMC2821372 DOI: 10.1186/1471-2164-11-18] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2009] [Accepted: 01/08/2010] [Indexed: 01/07/2023] Open
Abstract
BACKGROUND In vertebrates, late oogenesis is a key period during which the oocyte acquires its ability to resume meiosis (i.e. maturational competence) and to develop, once fertilized, into a normal embryo (i.e. developmental competence). However, the molecular mechanisms involved in these key biological processes are far from being fully understood. In order to identify key mechanisms conserved among teleosts and amphibians, we performed a comparative analysis using ovarian tissue sampled at successive steps of the maturational competence acquisition process in the rainbow trout (Oncorhynchus mykiss) and in the clawed toad (Xenopus laevis). Our study aimed at identifying common differentially expressed genes during late oogenesis in both species. Using an existing transcriptomic analysis that had previously been carried out in rainbow trout, candidate genes were selected for subsequent quantitative PCR-based comparative analysis. RESULTS Among the 1200 differentially expressed clones in rainbow trout, twenty-six candidate genes were selected for further analysis by real-time PCR in both species during late oogenesis. Among these genes, eight had similar expression profiles in trout and Xenopus. Six genes were down-regulated during oocyte maturation (cyp19a1, cyp17a1, tescalcin, tfr1, cmah, hsd11b3) while two genes exhibited an opposite pattern (apoc1, star). In order to document possibly conserved molecular mechanisms, four genes (star, cyp19a1, cyp17a1 and hsd11b3) were further studied due to their known or suspected role in steroidogenesis after characterization of the orthology relationships between rainbow trout and Xenopus genes. Apoc1 was also selected for further analysis because of its reported function in cholesterol transport, which may modulate steroidogenesis by regulating cholesterol bioavailability in the steroidogenic cells. CONCLUSIONS We have successfully identified orthologous genes exhibiting conserved expression profiles in the ovarian follicle during late oogenesis in both trout and Xenopus. While some identified genes were previously uncharacterized during Xenopus late oogenesis, the nature of these genes has pointed out molecular mechanisms possibly conserved in amphibians and teleosts. It should also be stressed that in addition to the already suspected importance of steroidogenesis in maturational competence acquisition, our approach has shed light on other regulatory pathways which may be involved in maturational and developmental competence acquisitions that will require further studies.
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Affiliation(s)
- Maella Gohin
- CNRS/IGDR (UMR 6061), IFR140 GFAS, Université de Rennes I, 2, Avenue du Pr, Léon Bernard, 35043 Rennes Cedex, France.
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Nakamura I, Kusakabe M, Young G. Differential suppressive effects of low physiological doses of estradiol-17beta in vivo on levels of mRNAs encoding steroidogenic acute regulatory protein and three steroidogenic enzymes in previtellogenic ovarian follicles of rainbow trout. Gen Comp Endocrinol 2009; 163:318-23. [PMID: 19422827 DOI: 10.1016/j.ygcen.2009.04.031] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/18/2008] [Revised: 04/22/2009] [Accepted: 04/27/2009] [Indexed: 11/23/2022]
Abstract
Numerous recent reports have demonstrated effects of estrogenic chemicals on reproductive physiology of fish. However, there is little information available on the regulation of ovarian steroidogenesis by physiological levels of endogenous steroids in teleosts. Therefore, we analyzed the levels of mRNAs encoding steroidogenic proteins in ovaries of E2-treated rainbow trout Oncorhynchus mykiss). Previtellogenic (perinucleolar oocyte stage) trout received either blank or E2 implants (0.1 microg, 1 microg or 10 microg/g BW) for 7 days in order to achieve low, medium and high physiological levels of E2 in plasma. Plasma E2 levels were measured using radioimmunoassay. Levels of mRNAs encoding steroidogenic acute regulatory protein (StAR), P450 side-chain cleavage enzyme (P450scc), 3beta-hydroxysteroid dehydrogenase (3beta-HSD) and P450 aromatase A (P450aromA) in the ovary were analyzed by real-time quantitative PCR. E2 levels in control animals were approximately 0.5 ng/ml. Levels in treated fish were approximately 1 ng/ml (0.1 microg implant), 2.6 ng/ml (1 microg implant) and 90 ng/ml (10 microg implant), within or just above the physiological range of immature and maturing female rainbow trout. StAR mRNA levels were significantly reduced by all E2 treatments. P450scc mRNA levels were not affected, but 3beta-HSD and P450arom mRNA levels were significantly decreased by the 1 and 10 microg E2/BW implants. These results indicate that E2, either directly or indirectly, downregulates expression of StAR and major steroidogenic enzyme genes in rainbow trout ovary. Furthermore, expression of the trout StAR gene seems particularly sensitive to E2.
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Affiliation(s)
- Ikumi Nakamura
- School of Aquatic and Fishery Sciences, University of Washington, Seattle, WA 98195, USA
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Esterhuyse MM, Helbing CC, van Wyk JH. Temporal expression of two cytochrome P450 aromatase isoforms during development in Oreochromis mossambicus, in association with histological development. COMPARATIVE BIOCHEMISTRY AND PHYSIOLOGY D-GENOMICS & PROTEOMICS 2008; 3:297-306. [PMID: 20483224 DOI: 10.1016/j.cbd.2008.08.003] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/24/2008] [Revised: 08/21/2008] [Accepted: 08/25/2008] [Indexed: 11/15/2022]
Abstract
Oreochromis mossambicus is targeted as a sentinel species for assay development to detect disruption of estrogen-dependent pathways in Southern Africa. Aromatase--an enzyme encoded by either of two cytochrome P450 19 (cyp19) genes in O. mossambicus is the only enzyme able to catalyze the aromatization of androgens to estrogens. As part of background studies relating to evaluating the use of early life stages of O. mossambicus as an endocrine disruptor screen, we investigated the tissue specificity and temporal expression of cyp19 transcripts, cyp19a (ovarian cyp19) and cyp19b (brain cyp19) during development and estrogen exposure. The cyp19a transcript was detected only in the ovaries of adults, and expression during development reflected this result as induction of cyp19a coincides with histological development of putative ovaries. Using primers that only identify the ovarian transcript, cyp19a transcript levels demonstrated a typical reflection of puberty - after an initial surge in cyp19a, juveniles expressed very low levels, which increased again at the time histologically discernable vitellogenic ovaries were detected. Moreover, we found evidence of putative alternate transcript of cyp19a whose function is currently unknown. cyp19b transcripts were expressed in brain and muscle tissue of both male and female adults, in addition to ovaries in females. During development, cyp19b transcript levels were increased coincidental with cyp19a at 20 days post fertilization but the expression pattern was distinct from that observed for cyp19a. These studies set the foundation for utilizing this native species as a possible indicator of endocrine disruption and accentuates the importance of understanding "normal" basal levels of transcript levels and the nature of amplification of QPCR targets.
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Affiliation(s)
- M M Esterhuyse
- Ecophysiology laboratory, Department of Botany and Zoology, University of Stellenbosch, Stellenbosch, South Africa
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