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Paul-Prasanth B, Bhandari RK, Kobayashi T, Horiguchi R, Kobayashi Y, Nakamoto M, Shibata Y, Sakai F, Nakamura M, Nagahama Y. Erratum: Estrogen oversees the maintenance of the female genetic program in terminally differentiated gonochorists. Sci Rep 2015. [PMCID: PMC3892714 DOI: 10.1038/srep03787] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
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Paul-Prasanth B, Bhandari RK, Kobayashi T, Horiguchi R, Kobayashi Y, Nakamoto M, Shibata Y, Sakai F, Nakamura M, Nagahama Y. Estrogen oversees the maintenance of the female genetic program in terminally differentiated gonochorists. Sci Rep 2013; 3:2862. [PMID: 24096556 PMCID: PMC3791451 DOI: 10.1038/srep02862] [Citation(s) in RCA: 67] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2013] [Accepted: 09/12/2013] [Indexed: 11/09/2022] Open
Abstract
The sexual plasticity of the gonads is not retained after the completion of sex differentiation in vertebrates, except in some hermaphroditic species. Here, we report that the depletion of estradiol-17β (E2) by aromatase inhibitors (AI) for up to six months resulted in a functional female-to-male sex reversal in sexually-mature adults of two gonochoristic fish species, Nile tilapia and medaka. The sex-reversed fish showed a typical male pattern of E2 and androgen levels, secondary sexual characteristics, and male-like sex behavior, producing fertile sperm. Conversely, co-treatment of E2 inhibited AI-induced sex reversal. In situ hybridization of medaka gonads during AI-induced sex reversal indicated that cysts on the dorsal side of the adult ovaries are the origin of germ cells and Sertoli cells in the newly formed testicular tissue. Gonochoristic fish maintain their sexual plasticity until adulthood and E2 plays a critical role in maintaining the female phenotype.
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Affiliation(s)
- B Paul-Prasanth
- 1] Solution-Oriented Research for Science and Technology (SORST) [2] Laboratory of Reproductive Biology, National Institute for Basic Biology, Okazaki 444-8585, Japan [3] [4]
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3
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Abstract
Among vertebrates, fishes show an exceptional range of reproductive strategies regarding the expression of their sexuality. Fish sexualities were categorized into gonochorism, synchronous/sequential hermaphrodite, or unisexual reproduction. In gonochoristic fishes, sex is determined genetically or by environmental factors. After sex determination, the gonads are differentiated into ovary or testis, with the sex remaining fixed for the entire life cycle. In contrast, some sequential hermaphrodite fishes can change their sex from male to female (protandrous), female to male (protogynous), or serially (bi-directional sex change) in their life cycle. In many cases, sex change is cued by social factors such as the disappearance of a male or female from a group. This unique diversity in fishes provides an ideal animal model to investigate sex determination and differentiation in vertebrates. This review first discusses genetic-orientated sex determination mechanisms. Then, we address the gonadal sex differentiation process in a gonochoristic fish, using an example of the Nile tilapia. Finally, we discuss various types of sex change that occur in hermaphrodite fishes.
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Affiliation(s)
- Y Kobayashi
- Tropical Biosphere Research Center, Sesoko Station, University of the Ryukyus, Motobu, Japan.
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Sreenivasulu G, Senthilkumaran B, Sudhakumari CC, Guan G, Oba Y, Kagawa H, Nagahama Y. 20β-hydroxysteroid dehydrogenase gene promoter: potential role for cyclic AMP and xenobiotic responsive elements. Gene 2012; 509:68-76. [PMID: 22835697 DOI: 10.1016/j.gene.2012.07.017] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2012] [Revised: 06/15/2012] [Accepted: 07/10/2012] [Indexed: 11/26/2022]
Abstract
Teleostean 20β-hydroxysteroid dehydrogenase (20β-HSD) is involved in final oocyte maturation and steroid hormone metabolism. It has structural and functional similarities to mammalian carbonyl reductases that are involved in the metabolism of endogenous carbonyl and xenobiotic compounds. To understand the transcriptional regulation of 20β-HSD, here we report the cloning of 20β-HSD promoter from two fish species, rainbow trout and air-breathing catfish. Analysis of the promoter motifs, in silico identified the presence of several sites for transcription factor binding including cAMP, xenobiotic and steroid hormone responsive elements. Luciferase reporter assays with progressive deletion constructs demonstrated that 20β-HSD type B of trout has no promoter activity while 20β-HSD type A of trout and catfish 20β-HSD promoters showed basal promoter activity. A TATA box flanked by a CAAT box is important for basal transcription. Deletion of cAMP responsive element in the promoter decreased basal promoter activity significantly. Reporter assays with forskolin and IBMX, drugs that increase intracellular cAMP induced the promoter activity over the basal level. Intriguingly, β-nafthoflavone, an arylhydrocarbon receptor ligand, induced the 20β-HSD promoter activity and is further evidenced by the induction of 20β-HSD expression in the livers of catfish, in vivo. These results demonstrate for the first time that 20β-HSD expression is not only modulated by cAMP but also by xenobiotics and further studies may provide significance to the ubiquitous distribution and broad substrate specificity of this enzyme.
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Affiliation(s)
- G Sreenivasulu
- Department of Animal Sciences, School of Life Sciences-Centre for Advanced Studies, University of Hyderabad, P.O. Central University, Hyderabad 500 046, Andhra Pradesh, India
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5
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Shen X, Cui J, Nagahama Y. The Forkhead Gene Family in Medaka: Expression Patterns and Gene Evolution. Cytogenet Genome Res 2012; 136:123-30. [DOI: 10.1159/000335898] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/03/2011] [Indexed: 11/19/2022] Open
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6
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Cui J, Shen X, Zhao H, Nagahama Y. Genome-Wide Analysis of Sox Genes in Medaka (Oryzias latipes) and Their Expression Pattern in Embryonic Development. Cytogenet Genome Res 2011; 134:283-94. [DOI: 10.1159/000329480] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/22/2011] [Indexed: 12/23/2022] Open
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7
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Abstract
The brain of teleost fish exhibits a significant degree of sexual plasticity, even in adulthood. This unique feature is almost certainly attributable to a teleost-specific sexual differentiation process of the brain, which remains largely unknown. To dissect the molecular basis of sexual differentiation of the teleost brain, we searched for genes differentially expressed between both sexes in the medaka brain. One gene identified in the screen, cyp19a1b, which encodes the steroidogenic enzyme aromatase, was selected for further analysis. As opposed to the situation in most vertebrates, medaka cyp19a1b is expressed at higher levels in the adult female brain than the male brain. The female-biased expression in the brain is consistent regardless of reproductive or diurnal cycle. Medaka cyp19a1b is expressed throughout the ventricular zones in wide areas of the brain, where, in most regions, females have a greater degree of expression compared to males, with the optic tectum exhibiting the most conspicuous predominance in females. Contrary to what is known in mammals, cyp19a1b expression exhibits neither a transient elevation nor a sex difference in medaka embryos. It is not until just before the onset of puberty that cyp19a1b expression in the medaka brain is sexually differentiated. Finally, cyp19a1b expression in the medaka brain is not under the direct control of sex chromosome genes but relies mostly, if not solely, on oestrogen derived from the gonad. These unique properties of aromatase expression in the brain probably contribute substantially to the less rigid sexual differentiation process, thus ensuring remarkable sexual plasticity in the teleost brain.
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Affiliation(s)
- K Okubo
- Department of Aquatic Bioscience, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Bunkyo, Tokyo, Japan.
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Raghuveer K, Sudhakumari CC, Senthilkumaran B, Kagawa H, Dutta-Gupta A, Nagahama Y. Gender differences in tryptophan hydroxylase-2 mRNA, serotonin, and 5-hydroxytryptophan levels in the brain of catfish, Clarias gariepinus, during sex differentiation. Gen Comp Endocrinol 2011; 171:94-104. [PMID: 21156177 DOI: 10.1016/j.ygcen.2010.12.003] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/03/2010] [Revised: 12/02/2010] [Accepted: 12/05/2010] [Indexed: 11/28/2022]
Abstract
Tryptophan hydroxylase (tph) is the key regulator in serotonin (5-HT) biosynthesis that stimulates the release of GnRH and gonadotropins by acting at the level of hypothalamo-hypophyseal axis. In brain, 5-HT is expressed predominantly in preoptic area-hypothalamus (POA-HYP) region in teleosts. Therefore, in the present study we isolated tph2 from catfish brain to evaluate its expression pattern in male and female brains during early development. Tph2 cloned from catfish brain is 2.768 Kb in length which encodes predicted protein of 488 amino acid residues. The characterization of recombinant tph2 was done by transient transfection in CHO cells. Tissue distribution of tph2 revealed ubiquitous expression except ovary. Real time PCR analysis in discrete regions of adult male brain revealed that tph2 mRNA was abundant in the POA-HYP and optic tectum+cerebellum+thalamus (OCT) regions. Differential expression of tph2 was observed at mRNA and protein levels in the POA-HYP and OCT regions of male and female brains during development that further correlate with the 5-hydroxytryptophan (5-HTP) and 5-HT levels measured using HPLC method in these regions of male and female brains. Tph2 immunoreactive neurons were observed in different regions of brain at 50 days post hatch using catfish specific tph2 antibody. Changes in tph2 mRNA expression, 5-HTP, and 5-HT levels in the POA-HYP+OCT region of brains of methyltestosterone and para-chlorophenylalanine treated fishes during development further endorse our results. Based on our results, we propose that the serotonergic system is involved in brain sex differentiation in teleosts.
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Affiliation(s)
- K Raghuveer
- Department of Animal Sciences, School of Life Sciences--Centre for Advanced Studies, University of Hyderabad, P.O. Central University, Hyderabad 500 046, Andhra Pradesh, India
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9
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Fernandino JI, Popesku JT, Paul-Prasanth B, Xiong H, Hattori RS, Oura M, Strüssmann CA, Somoza GM, Matsuda M, Nagahama Y, Trudeau VL. Analysis of sexually dimorphic expression of genes at early gonadogenesis of pejerrey Odontesthes bonariensis using a heterologous microarray. Sex Dev 2011; 5:89-101. [PMID: 21325793 DOI: 10.1159/000324423] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/15/2010] [Indexed: 12/29/2022] Open
Abstract
The process of morphological development of a differentiated gonad from an undifferentiated primordium is a very important step of gonadogenesis. Studies on sexually dimorphic gene expression are important to increase our understanding of this process and to investigate how environmental factors such as temperature can regulate gonadal development. The aim of this study was to identify putative genes involved in sex differentiation in pejerrey (Odontesthes bonariensis) reared at male- and female-producing temperatures (MPT and FPT, respectively) using a microarray heterologous from the medaka (Oryzias latipes), a closely phylogenetic species. Genes related to numerous processes presented higher expression at MPT, including those involved in muscular contraction, metabolic pathways, developmental processes, and reproduction. Genes induced by FPT were classified under the gene ontology terms of response to stimulus, transport and proteolysis. From genes selected for validation, at MPT ndrg3 expression was observed in the somatic cells, whereas pen-2 was detected in germ cells in the caudal portion of the gonads, where no apoptotic signals were observed. Finally, hsp90 was highly expressed in somatic cells of the gonads at the FPT. The results suggest that the interplay of pro-apoptotic and anti-apoptotic genes is important during the masculinization process and for the prevention of sterility following exposure to warm temperatures.
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Affiliation(s)
- J I Fernandino
- Laboratorio de Ictiofisiología y Acuicultura, Instituto de Investigaciones Biotecnológicas, Instituto Tecnológico de Chascomús (CONICET-UNSAM), Chascomús, Argentina. fernandino @ intech.gov.ar
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Sudhakumari CC, Senthilkumaran B, Raghuveer K, Wang DS, Kobayashi T, Kagawa H, Krishnaiah C, Dutta-Gupta A, Nagahama Y. Dimorphic expression of tryptophan hydroxylase in the brain of XX and XY Nile tilapia during early development. Gen Comp Endocrinol 2010; 166:320-9. [PMID: 19925800 DOI: 10.1016/j.ygcen.2009.11.009] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/27/2009] [Revised: 10/15/2009] [Accepted: 11/10/2009] [Indexed: 12/11/2022]
Abstract
Serotonin (5-HT) is well known for modulating the release of GnRH and gonadotropin in teleosts. Reports on increased female:male ratio after the blockade of 5-HT biosynthesis proposed a role for 5-HT in brain sex differentiation. Two types of tryptophan hydroxylase (Tph), rate-limiting enzyme in the biosynthesis of 5-HT were cloned from vertebrates. In the present study, we cloned Tph from brain and evaluated its importance during early development of XX and XY Nile tilapia. Tph cloned from tilapia brain is 1888 bp in length and it encodes predicted protein of 462 amino acid residues. Tph activity of tilapia was confirmed by demonstrating the conversion of L-tryptophan to 5-hydroxy tryptophan by the recombinant protein after transient transfection of this cDNA clone in COS-7 cells. Northern blot identified single transcript around 2kb in male brain. Tissue distribution of Tph revealed high abundance in brain, kidney, liver and testis. Semi-quantitative RT-PCR revealed exclusive expression of Tph in the male brain from 5 to 20 days post hatch (dph) while in the female brain, it was from 25 dph. These results were authenticated by localization of Tph transcripts in olfactory bulb-telencephalon region of 11 dph male brain using in situ hybridization. Tph immunoreactivity (-ir) was also evident in the nucleus preopticus-periventricularis area of male brain as early as 12 dph. However, Tph-ir was observed in several regions of both male and female brain without any distinction from 30 dph. Dimorphic expression pattern of Tph during early brain development around the critical period (7-21 dph) of gonadal sex determination and differentiation may implicate a role for Tph in brain sex differentiation of tilapia.
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Affiliation(s)
- C C Sudhakumari
- Department of Animal Sciences, School of Life Sciences-Centre of Advanced Study, University of Hyderabad, P.O. Central University, Hyderabad 500046, Andhra Pradesh, India.
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11
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Chen W, Cao M, Yang Y, Nagahama Y, Zhao H. Expression pattern of prmt5 in adult fish and embryos of medaka, Oryzias latipes. Fish Physiol Biochem 2009; 35:325-332. [PMID: 19578939 DOI: 10.1007/s10695-008-9233-2] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/31/2008] [Accepted: 05/09/2008] [Indexed: 05/28/2023]
Abstract
DNA methylation is an important biochemical epigenetic determinant of gene expression in cells and therefore actively involved in gene regulation, chromosomal conformation, and protein activity. Protein arginine methyltransferases (PRMTs) play a major role in the methylation of proteins that have an arginine residue, catalyzing both the asymmetric dimethylation of arginine (aDMA) and symmetric dimethylation of arginine (sDMA). PRMT5, a type II PRMT which catalyzes sDMA, has been shown to have a pivotal role in pole plasm assembly and germ cell development in Drosophila and also to be an associate factor of Blimp1 for germ cell development in mouse. Here, we report a homolog of prmt5 identified in medaka, Oryzias latipes, which was detected in the brain, gill, muscle, heart, liver, spleen, intestine, testis and ovary of adult fish by reverse transcriptase-PCR. The expression of prmt5 in the gonads is restricted to oocytes of the ovary, spermatogonia, and spermatocytes of testis. The prmt5 transcripts were detected as early as the one-cell stage and in all the tissues of embryos during embryogenesis. In summary, prmt5 is a maternal determinant factor of embryogenesis of medaka, possibly playing an important role in oogenesis and spermatogenesis in adult medaka.
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Affiliation(s)
- W Chen
- Hubei Key Laboratory of Genetic Regulation and Integrative Biology, School of Life Sciences, Huazhong Normal University, Wuhan, 430079, China
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12
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Senthilkumaran B, Sudhakumari CC, Wang DS, Sreenivasulu G, Kobayashi T, Kobayashi HK, Yoshikuni M, Nagahama Y. Novel 3beta-hydroxysteroid dehydrogenases from gonads of the Nile tilapia: phylogenetic significance and expression during reproductive cycle. Mol Cell Endocrinol 2009; 299:146-52. [PMID: 19084575 DOI: 10.1016/j.mce.2008.11.008] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/05/2008] [Revised: 11/06/2008] [Accepted: 11/11/2008] [Indexed: 11/26/2022]
Abstract
Multiple forms of 3beta-hydroxysteroid dehydrogenase/isomerase (3beta-HSD) and their differential tissue expression pattern have not been shown in any lower vertebrates. In the present study, we report cloning of two novel 3beta-HSDs and two variants from gonads of the Nile tilapia. 3beta-HSD cDNAs encode two peptides of 375 (3beta-HSD type-I/variant 1) and 367 (3beta-HSD type-II/variant 1) amino acid residues that share 31.9% homology. 3beta-HSD type-I/variant 1 shared high homology with other piscine counterparts while 3beta-HSD type-II/variant 1 exhibited homology to mammalian DeltaC27-3beta-HSD and multifunctional viral 3beta-HSD. The latter seems to be ancient form among vertebrates. Transiently transfected 3beta-HSDs' open reading frames in COS-7 cells converted exogenous pregnenolone/androsta-5-ene-3beta-17beta-diol to progesterone/testosterone. Tissue distribution pattern of 3beta-HSDs by RT-PCR revealed varied expression pattern. Northern blot analysis of 3beta-HSDs demonstrated steady or gradual rise in transcripts level at different gonadal stages. These data revealed the importance of novel 3beta-HSDs in teleosts and also provided phylogenetic significance.
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Affiliation(s)
- B Senthilkumaran
- Laboratory of Reproductive Biology, National Institute for Basic Biology, Myodaiji, Okazaki 444-8585, Japan.
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13
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Mittelholzer C, Andersson E, Taranger GL, Consten D, Hirai T, Senthilkumaran B, Nagahama Y, Norberg B. Molecular characterization and quantification of the gonadotropin receptors FSH-R and LH-R from Atlantic cod (Gadus morhua). Gen Comp Endocrinol 2009; 160:47-58. [PMID: 18992749 DOI: 10.1016/j.ygcen.2008.10.015] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/09/2008] [Revised: 09/29/2008] [Accepted: 10/15/2008] [Indexed: 10/21/2022]
Abstract
In order to elucidate regulatory mechanisms during puberty final oocyte maturation and spawning, full-length sequences coding for the receptors for follicle-stimulating hormone (FSH-R) and luteinizing hormone (LH-R) were isolated from female Atlantic cod (Gadus morhua) by a RACE-PCR based strategy. The nucleotide and amino acid sequences showed high homologies with the corresponding sequences of other fish species but contained some distinct differences. Conserved features important for functionality, such as a long N-terminal extracellular domain (ECD), seven transmembrane domains and a short C-terminal intracellular domain, were identified in both predicted proteins. Partial genomic sequences for these genes were also determined, allowing the design of mRNA-specific quantitative PCR assays. Due to suspected alternative splicing during expression of these genes, additional real-time PCR assays detecting variants containing the membrane-anchoring domain were established. Besides the expected expression of FSH-R and LH-R mRNA in the gonads similarly strong signals for LH-R were also obtained in male gill, and in female and male brain. When relative expression was analysed at different stages of sexual maturation, levels for FSH-R increased moderately during gonadal growth whereas those of LH-R showed a high peak at spawning.
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Affiliation(s)
- C Mittelholzer
- Institute of Marine Research Austevoll, Storebø, Norway.
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Kobayashi T, Nagahama Y. Molecular Aspects of Gonadal Differentiation in a Teleost Fish, the Nile Tilapia. Sex Dev 2009; 3:108-17. [DOI: 10.1159/000223076] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2008] [Accepted: 01/08/2009] [Indexed: 11/19/2022] Open
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Swapna I, Sudhakumari CC, Sakai F, Sreenivasulu G, Kobayashi T, Kagawa H, Nagahama Y, Senthilkumaran B. Seabream GnRH immunoreactivity in brain and pituitary of XX and XY Nile tilapia,Oreochromis niloticusduring early development. ACTA ACUST UNITED AC 2008; 309:419-26. [DOI: 10.1002/jez.467] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
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Abstract
The neuropeptide gonadotropin-releasing hormone (GnRH) has a central role in the neural control of vertebrate reproduction. This review describes an overview of what is currently known about GnRH in vertebrates in the context of its structural and functional evolution. A large body of evidence has demonstrated the existence of three paralogous genes for GnRH (GnRH1, GnRH2 and GnRH3) in the vertebrate lineage. They are most probably the products of whole-genome duplications that occurred early in vertebrate evolution. Although GnRH3 has been identified only in teleosts, comparative genomic analyses indicated that GnRH3 has not arisen from a teleost-specific genome duplication, but has been derived from an earlier genome duplication in an ancestral vertebrate, followed by its loss in the tetrapod lineage. A loss of other paralogous genes has also occurred independently in different vertebrate lineages, leading to species-specific differences in the organization of the GnRH system. In addition to the GnRH3 gene, the GnRH2 gene has been deleted or silenced in certain mammalian species, while some teleosts seem to have lost the GnRH1 or GnRH3 gene. The duplicated GnRH genes have undergone subfunctionalization during the evolution of vertebrates; GnRH1 has become the major stimulator of gonadotropins and probably other pituitary hormones as well, whereas GnRH2 and GnRH3 would have functioned as neuromodulators, affecting reproductive behaviour. Conversely, in cases where a paralogous gene for GnRH has been lost, one of the remaining paralogues appears to have adopted its role.
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Affiliation(s)
- K Okubo
- Laboratory of Reproductive Biology, National Institute for Basic Biology, Okazaki, Aichi, Japan.
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17
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Mittelholzer C, Andersson E, Consten D, Hirai T, Nagahama Y, Norberg B. 20 beta-hydroxysteroid dehydrogenase and CYP19A1 are differentially expressed during maturation in Atlantic cod (Gadus morhua). J Mol Endocrinol 2007; 39:319-28. [PMID: 17909270 DOI: 10.1677/jme-07-0070] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
In order to better quantify the molecular mechanisms regulating final oocyte maturation and spawning, complete coding sequences with partially or fully untranslated regions for the steroidogenic enzymes, cytochrome P450 aromatase and 20 beta-hydroxysteroid dehydrogenase, were cloned from ovaries of Atlantic cod (Gadus morhua). The nucleotide and amino acid sequences showed high homologies with the corresponding sequences of other fish species, and conserved features important for functionality were identified in both predicted proteins. The sequences of the corresponding genomic loci were also determined, allowing the design of mRNA-specific quantitative PCR assays. As a reference gene for the real-time RT-PCR assays, eukaryotic elongation factor 1 alpha was chosen, and the mRNA as well as the genomic sequence was determined. In addition, a real-time quantitative PCR assay for the 18S rRNA was adapted to be used in cod. Analysis of immature and maturing female cod from July to January respectively showed that the enzyme genes showed the expected quantitative changes associated with physiological regulation. However, mRNA for eukaryotic elongation factor 1 alpha, and to a lesser extent even 18S rRNA, showed variable expression in these samples as well. To find accurate standards for real-time PCR in such a dynamic organ as the cod ovary is not an easy task, and several possible solutions are discussed.
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Affiliation(s)
- C Mittelholzer
- Institute of Marine Research, Austevoll Research Station, N-5392 Storebø, Norway.
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Abstract
Under cultivation conditions, male Japanese eels (Anguilla japonica) have immature testes containing only spermatogonia together with inactive testicular somatic cells, Leydig cells and Sertoli cells. Using a recently developed organ culture system for eel testes, we have shown that hormonal induction of spermatogenesis in eel testes involves gonadotropin stimulation of Leydig cells to produce 11-ketotestosterone, a potent androgen in fish. In turn, 11-ketotestosterone activates Sertoli cells to stimulate premitotic spermatogonia to complete spermatogenesis. Our current research focuses on the isolation and characterization of genes that show altered expression in eel testes during gonadotropin-induced spermatogenesis. One up-regulated and three down-regulated genes have been isolated. Northern blot analysis and in situ hybridization reveal that mRNA for activin B is absent in testes before gonadotropin injection and is abundant in Sertoli cells in testes injected with gonadotropin for one to six days after injection. This stimulation of activin B mRNA is accompanied by spermatogonial proliferation. Gonadotropin treatment also causes a rapid rise in the testicular concentrations of mRNA for 3 beta-hydroxysteroid dehydrogenase, the rate-limiting enzyme for gonadotropin-induced 11-ketotestosterone production. We have also obtained three down-regulated cDNAs which are abundant in testes before gonadotropin treatment and disappear almost completely in testes one day after gonadotropin injection.
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Affiliation(s)
- Y Nagahama
- Department of Developmental Biology, National Institute for Basic Biology, Okazaki
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Zhou LY, Wang DS, Senthilkumaran B, Yoshikuni M, Shibata Y, Kobayashi T, Sudhakumari CC, Nagahama Y. Cloning, expression and characterization of three types of 17beta-hydroxysteroid dehydrogenases from the Nile tilapia, Oreochromis niloticus. J Mol Endocrinol 2005; 35:103-16. [PMID: 16087725 DOI: 10.1677/jme.1.01801] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
In order to elucidate the roles of 17beta-HSDs in fish gonadal steroidogenesis, three types of 17beta-HSDs (17beta-HSD1, 17beta-HSD8 and putative 17beta-HSD12) were cloned and characterized from the Nile tilapia, Oreochromis niloticus. The cloned cDNAs of 17beta-HSD type 1, 8 and 12 were 1504, 1006 and 1930 bp long, with open reading frames encoding proteins of 289, 256 and 314 aminoacids, respectively. Tissue distribution pattern analyzed by RT-PCR and Northern blot showed that 17beta-HSD1 was dominantly expressed in the ovary, while the putative 17beta-HSD12, one of the two duplicates found in fish, is a male specific enzyme and expressed exclusively in testis (detected by RT-PCR only). On the other hand, 17beta-HSD8 was expressed in the brain, gill, heart, liver, intestine, gonad, kidney and muscle of both male and female. Enzymatic assays of the three types of 17beta-HSDs were performed using recombinant proteins expressed in E. coli or HEK 293 cells. Tilapia 17beta-HSD1 expressed in E. coli had the preference for NADP(H) as cofactor and could catalyze the inter-conversion between estrone and estradiol efficiently as well as the inter-conversion between androstenedione and testosterone, but less efficiently. Tilapia 17beta-HSD8 recombinant protein expressed in HEK 293 cells could catalyze the conversion of testosterone to androstenedione, as well as the inter-conversion between estrone and estradiol. However, the putative 17beta-HSD12 expressed in E. coli or in HEK 293 cells showed no conversion to any of the four substrates tested in this study. Based on enzyme characterization and tissue distribution, it is plausible to attribute crucial roles to 17beta-HSDs in the gonadal steroidogenesis of teleosts.
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Affiliation(s)
- L Y Zhou
- Laboratory of Reproductive Biology, Department of Developmental Biology, National Institute for Basic Biology, Okazaki 444-8585, Japan
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Wang DS, Senthilkumaran B, Sudhakumari CC, Sakai F, Matsuda M, Kobayashi T, Yoshikuni M, Nagahama Y. Molecular cloning, gene expression and characterization of the third estrogen receptor of the Nile tilapia, Oreochromis niloticus. Fish Physiol Biochem 2005; 31:255-266. [PMID: 20035467 DOI: 10.1007/s10695-006-0033-2] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Estrogens are essential for many reproductive and non-reproductive functions. In teleosts, it is well-known that several subtypes of estrogen receptors are required for the precise action of estrogens. Present study describes the cloning of the third estrogen receptor, ER- beta2, from the Nile tilapia by EST sequencing coupled microarray. The cloned ER-beta2 showed 77.7% amino acid identity with the reported Atlantic croaker ER-beta. Three ERs, ER-alpha, ER-beta1 and ER-beta2, from the fugu genome were also isolated to analyze their gene structures. Comparison of the intron/exon boundaries and exon numbers of fugu, tilapia, rainbow trout and zebrafish, and phylogenetic analysis of 63 ER sequences revealed that ER-beta probably underwent two successive lineage-specific duplications in teleost. The former took place only in zebrafish lineage, and the latter took place in advanced teleosts without the zebrafish lineage, whereas no duplication of the ER-alpha gene has been detected. Tissue distribution analysis by RT-PCR revealed that tilapia ER-alpha and ER-beta1 were expressed ubiquitously, whereas ER-beta2 is expressed only in the pituitary, liver, intestine, kidney and gonads, with the highest expression in the testis and the lowest level in the ovary. Northern blot analysis detected a single transcript of about 3.4 kb in the testis but not in the ovary mRNAs. In transient transfection assays using human embryonic kidney 293 (HEK293) cells, tilapia ER-beta2 showed estrodiol-17beta dependent transactivation.
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Affiliation(s)
- D S Wang
- Laboratory of Reproductive Biology, National Institute for Basic Biology, Okazaki, 444-8585, Japan
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21
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Supriya A, Raghuveer K, Swapna I, Rasheeda MK, Kobayashi T, Nagahama Y, Gupta AD, Majumdar KC, Senthilkumaran B. Thyroid hormone modulation of ovarian recrudescence of air-breathing catfish Clarias gariepinus. Fish Physiol Biochem 2005; 31:267-270. [PMID: 20035468 DOI: 10.1007/s10695-006-0034-1] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
In the present study, thiourea-induced thyroid hormone depletion and thyroxine (T(4)) 'overdose' were used as a strategy to understand the influence of thyroid hormones on ovarian recrudescence of juvenile (3-months-old), immature (8-months-old) and adult (1-year-old) air-breathing catfish, Clarias gariepinus. Thiourea-induced thyroid hormone depletion in juvenile catfish impaired ovarian development, but no significant effect was observed in immature catfish and during late stage of ovarian recrudescence of mature catfish. T(4) treatment in females undergoing late stages of ovarian recrudescence induced rapid oocyte growth by promoting its early entry into maturational phase as evident from the presence of more number of vitellogenic and post-vitellogenic follicles, decrease in aromatse immunoreactivity and reduced estradiol-17beta levels. Hence, thyroid hormones have an important role to play during early stages of ovarian development and vitellogenesis of catfish and also indicating that thyroid has a stage dependent effect on ovary.
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Affiliation(s)
- A Supriya
- Department of Animal Sciences, School of Life Sciences, University of Hyderabad, P.O. Central University, Gachibowli, Hyderabad, 500 046, India
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22
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Raghuveer K, Garhwal R, Wang DS, Bogerd J, Kirubagaran R, Rasheeda MK, Sreenivasulu G, Bhattachrya N, Tarangini S, Nagahama Y, Senthilkumaran B. Effect of methyl testosterone- and ethynyl estradiol-induced sex differentiation on catfish, Clarias gariepinus: expression profiles of DMRT1, Cytochrome P450aromatases and 3 beta-hydroxysteroid dehydrogenase. Fish Physiol Biochem 2005; 31:143-147. [PMID: 20035448 DOI: 10.1007/s10695-006-0016-3] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
The objective of the present study is to observe the effect of exogenous steroids, methyl testosterone (MT) and ethynyl estradiol (EEL) on gonadal differentiation and analyze its effect on the expression of several genes during testicular and ovarian differentiation in juvenile catfish. Exogenous hormone treatments (MT and EEL) were given by immersion at different days of hatching. The histological analysis revealed that the EEL- and MT-treatments resulted in the initiation of ovarian and testicular differentiation, respectively. This is further supported by specific expression of two forms of DMRT1 in the MT-treated group but not in the EEL-treated group at 47 days after hatching (dah). The reverse is true for the expression of ovarian aromatase. Results of the semi-quantitative RT-PCR show that brain aromatase transcript levels are high in 47 dah control (histologically female) and 47 dah EEL-treated fish, as compared to 47 dah MT-treated fish. At 60 dah, brain aromatase showed elevation in its expression. Interestingly, the expression pattern of 3 beta-HSD did not show any change in EEL- and MT-treated fish. The present study also provides a strategy to study sex differentiation, for those species where genetic sex population is unavailable.
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Affiliation(s)
- K Raghuveer
- Department of Animal Sciences, School of Life Sciences, University of Hyderabad, Gachibowli, Hyderabad, 500 046, India
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Sakai F, Swapna I, Sudhakumari CC, Ganesh MVNL, Kagawa H, Kobayashi T, Fan H, Nagahama Y, Senthilkumaran B. Immunocytochemical localization of gonadotropins during the development of XX and XY Nile tilapia. Fish Physiol Biochem 2005; 31:177-181. [PMID: 20035455 DOI: 10.1007/s10695-006-0021-6] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Gonadal development and steroidogenesis in teleosts is regulated by two gonadotropic hormones; luteinizing hormone (LH) and follicle-stimulating hormone (FSH). Earlier studies in tilapia have shown that FSH-beta and LH-beta appear by 14 days after hatching (dah), results from the current study corroborate with these previous reports in tilapia. Here we demonstrate the appearance of LH in pituitary between 14 and 20 dah. In addition to this the present study primarily focuses on any possible differences in appearance of LH-beta and FSH-beta immunoreactivity between XX and XY population of Nile tilapia. LH immunoreactivity was found to be lower in pituitary of XX fish when compared to XY fish. The development of FSH-beta immunoreactivity in pituitary of the Nile tilapia is also presented. Overall, it remains to be established what significance these findings on the appearance of gonadotropins hold for sex differentiation in tilapia.
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Affiliation(s)
- F Sakai
- Laboratory of Reproductive Biology, National Institute of Basic Biology, Okazaki, 444-8585, Japan
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24
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Sudhakumari CC, Senthilkumaran B, Kobayashi T, Kajiura-Kobayashi H, Wang DS, Yoshikuni M, Nagahama Y. Ontogenic expression patterns of several nuclear receptors and cytochrome P450 aromatases in brain and gonads of the Nile tilapia Oreochromis niloticus suggests their involvement in sex differentiation. Fish Physiol Biochem 2005; 31:129-135. [PMID: 20035446 DOI: 10.1007/s10695-006-0014-5] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Using semi-quantitative reverse transcriptase polymerase chain reaction we analyzed the ontogenic expression patterns of several nuclear receptors (estrogen receptors [ERalpha and beta], androgen receptors [ARalpha and beta], Ad4BP/SF-1 and Dax-1) and cytochrome P450 aromatases (brain and ovarian types) in whole brain and gonads of the Nile tilapia. ERalpha and beta transcripts were evident in both sexes with a high expression of ERalpha in females at 0 day after hatching (0 dah). ARalpha appeared early (0 dah) in males and while in females at 25 dah. Among the two types of cytochrome P450 aromatases, the expression of the brain type (bP450arom) but not the ovarian type (oP450arom) was evident from 0 to 90 dah in the whole brain of both males and females. Expression of Ad4BP/SF-1 in female brain began from 0 dah but in male brain at 5 dah. Expression of Dax-1 began at 0 dah and it was higher throughout in male brain than that of the female brain. In gonads, ERalpha and beta transcripts were evident in both sexes with slight variation. In females, both oP450arom and Ad4BP/SF-1 amplicons were evident at 15 dah. In males, although faint expressions of Ad4BP/SF-1 amplicons were evident at early duration of development, oP450arom did not appear until 90 dah. Conversely, expression of bP450arom was observed throughout in the developing testis with varied pattern while in developing ovary it was evident till 15 dah and reappeared only after 90 dah. Taken together, present results suggest that brain acts merely as a synchronizer in the sex differentiation process initiated by gonadal cues/factors in the Nile tilapia.
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Affiliation(s)
- C C Sudhakumari
- Laboratory of Reproductive Biology, Department of Developmental Biology, National Institute for Basic Biology, Okazaki, 444-8585, Japan,
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Abstract
We have used various genetic and molecular approaches to investigate the mechanisms of sex determination and gonadal sex differentiation in fish. DMY was identified as the sex-determining gene of medaka. In tilapia, endogenous estrogens act as natural inducers of ovarian differentiation, while DMRT1 may be important for testicular differentiation. The roles of these regulators in sex determination and gonadal sex differentiation were ascertained using a gene or hormonal blockade strategy.
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Affiliation(s)
- Y Nagahama
- Laboratory of Reproductive Biology, Department of Developmental Biology, National Institute for Basic Biology, Okazaki, 444-8585, Japan,
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Nagahama Y, Okina T, Suzuki N, Nabatame H, Matsuda M. The cerebral correlates of different types of perseveration in the Wisconsin Card Sorting Test. J Neurol Neurosurg Psychiatry 2005; 76:169-75. [PMID: 15654026 PMCID: PMC1739495 DOI: 10.1136/jnnp.2004.039818] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
OBJECTIVES To explore the neural substrates corresponding to the perseverative errors in the Wisconsin Card Sorting Test (WCST). METHODS The study examined the correlations between the WCST performances and the SPECT measurements of regional cerebral blood flow (rCBF) in subjects with neurodegenerative dementia. Negative non-linear correlations between the rCBF and the two different types of the perseverative errors ("stuck-in-set" and "recurrent" perseverative errors) were calculated on a voxel basis and volume-of-interest basis in the mixed groups of 72 elderly and dementia patients. RESULTS The stuck-in-set perseverative error was associated with the reduced rCBF in the rostrodorsal prefrontal cortex, whereas the recurrent perseverative error was related to the left parietal activity but not to the prefrontal activity. CONCLUSIONS These findings augment evidence that the rostrodorsal prefrontal cortex crucially mediates attentional set shifting, and suggest that the stuck-in-set perseverative errors would be a true pathognomonic sign of frontal dysfunction. Moreover, this study shows that the recurrent perseverative errors may not be associated closely with the prefrontal function, suggesting that this error and the stuck-in-set error should be differentially estimated in the WCST.
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Affiliation(s)
- Y Nagahama
- Department of Geriatric Neurology, Shiga Medical Center, Moriyama-city, Shiga 524-8524, Japan.
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27
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Kobayashi T, Kajiura-Kobayashi H, Nagahama Y. Induction of XY sex reversal by estrogen involves altered gene expression in a teleost, tilapia. Cytogenet Genome Res 2003; 101:289-94. [PMID: 14684997 DOI: 10.1159/000074351] [Citation(s) in RCA: 106] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2003] [Accepted: 07/15/2003] [Indexed: 11/19/2022] Open
Abstract
To clarify the importance of endogenous estrogens during sex differentiation in a teleost fish, the Nile tilapia, we examined the target events for endogenous estrogens and their role during gonadal sex differentiation. The expression of CYP19a (P450arom) precedes any morphological gonadal sex differentiation. Further to these findings, the treatment of XX fry with non-steroidal aromatase inhibitor (AI), Fadrozole, from seven to 14 days after hatching caused complete sex reversal to functional males. The XX sex reversal induced by AI was rescued completely with simultaneous estrogen treatment. We also found that XY fry treated with estrogen, before the appearance of morphological sex differences, caused complete sex reversal from males to females. Taken together, these results suggest that endogenous estrogens are required for ovarian differentiation. To identify the down-stream gene products of estrogen during ovarian differentiation, we performed subtractive hybridization using mRNA derived from normal and estrogen treated XY gonads. Two out of ten gene products were expressed in germ cells, whereas the others were expressed in somatic cells.
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Affiliation(s)
- T Kobayashi
- Laboratory of Reproductive Biology, National Institute for Basic Biology, Okazaki, Japan.
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28
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Jiang JQ, Wang DS, Senthilkumaran B, Kobayashi T, Kobayashi HK, Yamaguchi A, Ge W, Young G, Nagahama Y. Isolation, characterization and expression of 11beta-hydroxysteroid dehydrogenase type 2 cDNAs from the testes of Japanese eel (Anguilla japonica) and Nile tilapia (Oreochromis niloticus). J Mol Endocrinol 2003; 31:305-15. [PMID: 14519098 DOI: 10.1677/jme.0.0310305] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
The Japanese eel (Anguilla japonica) and Nile tilapia (Oreochromis niloticus) 11beta-hydroxysteroid dehydrogenase type 2 (11beta-HSD2) cDNAs were isolated from their respective testes cDNA libraries. The cDNAs predict two peptides of 436 and 406 amino acid residues that share about 42% homology with mammalian 11beta-HSD type 2 proteins. Analysis of the tissue distribution pattern by RT-PCR reveals that 11beta-HSD2 is expressed in a wide variety of tissues in tilapia, with higher expression in kidney and gill of both sexes, and with the highest expression in testis. 11beta-Dehydrogenase activity of the eel 11beta-HSD2 was confirmed by demonstrating the conversion of cortisol to cortisone by the recombinant protein after transient expression of this cDNA clone in COS-1 cells. Bands of approximately 2.7 and approximately 3.8 Kb were detected in Northern blot of eel and tilapia testes respectively, which is consistent with the cloned cDNA sizes of the two species. Northern blot analysis also revealed that the expression of the eel testis 11beta-HSD2 gene could be induced by human chorionic gonadotropin (hCG) injection, implying a role of 11beta-HSD2 in hCG-induced 11-ketotestosterone production and spermatogenesis in the Japanese eel.
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Affiliation(s)
- J Q Jiang
- Laboratory of Reproductive Biology, National Institute for Basic Biology, Okazaki 444-8585, Japan
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29
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Tokumoto M, Nagahama Y, Tokumoto T. Molecular cloning of cDNA encoding polypeptide chain elongation factor 1alpha from goldfish (Carassius auratus). DNA Seq 2001; 12:419-24. [PMID: 11913790 DOI: 10.3109/10425170109084468] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
The goldfish homologue of polypeptide chain elongation factor-1alpha (EF-1alpha) isolated from the ovary of the goldfish is described. The deduced amino acid sequence is highly homologous to EF-1alpha from other species. Analysis of its tissue distribution revealed a single 1.7 kilobase message ubiquitous among various tissues.
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Affiliation(s)
- M Tokumoto
- Laboratory of Reproductive Biology, National Institute for Basic Biology, Okazaki, Japan.
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30
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Abstract
In fish and amphibians, B-type lamins are divided into somatic (B1, B2) and oocyte-type (B3) lamins. In this study, we purified nuclear lamins from rainbow trout erythrocytes, raised an anti-lamin monoclonal antibody (L-200) that recognizes goldfish somatic-lamins, and isolated cDNAs encoding goldfish B-type lamins (B1 and B2) from a goldfish cell culture cDNA library. Goldfish B-type lamins are structurally similar to lamins found in other vertebrates with minor amino acid substitutions in the conserved region. Western blot analysis showed that goldfish oocytes contained mainly GV-lamin B3 as well as some somatic lamins. Laser-confocal microscope observations revealed that lamin B3 was present only in GV nuclear lamina, whereas somatic lamins were present in dense fibrillar structures throughout nuclear gels of isolated GVs. Similar nuclear filamentous structures were also observed in GVs of paraffin embedded oocytes. Epitope mapping indicated that L-200 recognized a conserved region containing a short stretch of the alpha-helix coiled-coil rod domain (Y(E/Q)(Q/E)LL). A similar motif is also present in other cytoplasmic intermediate filaments (i.e., vimentin, desmin, peripherin and GFAP). Taken together, these findings suggest that lamins or lamin-related intermediate filaments are an important component of the interior architecture of goldfish vitellogenic oocyte nuclei (GVs).
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Affiliation(s)
- A Yamaguchi
- Department of Developmental Biology, National Institute for Basic Biology, Okazaki, Japan
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31
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Lee YH, Du JL, Yueh WS, Lin BY, Huang JD, Lee CY, Lee MF, Lau EL, Lee FY, Morrey C, Nagahama Y, Chang CF. Sex change in the protandrous black porgy, Acanthopagrus schlegeli: a review in gonadal development, estradiol, estrogen receptor, aromatase activity and gonadotropin. J Exp Zool 2001; 290:715-26. [PMID: 11748620 DOI: 10.1002/jez.1122] [Citation(s) in RCA: 70] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Black porgy, Acanthopagrus schlegeli Bleeker, a marine protandrous hermaphrodite, is functional male for the first two years of life but begins to sexually change to female after the third year. Testicular tissue and ovarian tissue was separated by connective tissue in the bisexual gonad. This sex pattern provides a very good model to study the endocrine mechanism of sex change in fish. The annual profiles of plasma estradiol, vitellogenin and 11-ketotestosterone concentrations in males were significantly different from those in the three-year-old females. Significantly high levels of plasma estradiol during the prespawning/spawning season and low levels of plasma 11-ketotestosterone during the spawning season were observed in the inversing females. No difference of plasma testosterone levels was observed in males and females. Oral administration of estradiol stimulated high levels of gonadal aromatase activity, plasma gonadotropin II levels and sex change in the two-year-old fish. Exogenous estradiol administered for 5-6 months induced a reversible sex change in one- and two-year-old fish. The sensitive period for estradiol treatment of sex change is from early prespawning to spawning season. Implantation with testosterone for more than a year could not block the natural sex change in three-year-old fish. Exogenous aromatase inhibitors (1,4,6-androstatriene-3,17-dione or fadrozole) suppressed aromatase activity in the brain. Oral administration with aromatase inhibitors for a year further inhibited the natural sex change in three-year-old black porgy and all fish became functional male with spermiation. Estrogen receptor alpha gene in the ovarian tissue of bisexual gonad is significantly less expressed than that in the vitellogenic ovary of female on the basis of reverse-transcription polymerase-chain reaction. There was no difference in the annual profiles of the plasma gonadotropin II levels in the males and natural inversing females. Plasma gonadotropin II levels were significantly higher in estradiol-treated group than those in the control. It is concluded that estradiol, aromatase activity and estrogen receptor in the ovarian tissue play an important role in the natural and controlled sex change in black porgy. The association of gonadotropin and sex change in black porgy is not clear.
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Affiliation(s)
- Y H Lee
- Department of Aquaculture, National Taiwan Ocean University, Keelung 20224, Taiwan, Republic of China
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Nagahama Y, Okina T, Nabatame H, Matsuda M, Murakami M. [Clock drawing in dementia: its reliability and relation to the neuropsychological measures]. Rinsho Shinkeigaku 2001; 41:653-8. [PMID: 11993183] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/24/2023]
Abstract
To examine the reliability and validity of clock drawing (CD) for evaluating dementia patients in Japan, we investigated the CD performance and its relation to several neuropsychological tests in 150 demented patients including 105 patients with Alzheimer disease and 30 age- and education-matched non-demented subjects (16 patients with mild cognitive impairment and 14 normals). Patients were also evaluated using the Mini-mental State Exam (MMSE), Wechsler Memory Scale (WMS), Kohs Block Design, and word fluency. CD was scored using the Shulman method. CD scores showed a high interrater reliability (r = 0.97). CD by non-demented subjects was essentially normal. As a screening test for Alzheimer disease (AD, mean MMSE = 18.0), CD had a sensitivity of 57.1% and a specificity of 96.7%. However, four of eight AD patients who showed normal MMSE score (> or = 24) drew abnormal clocks. CD scores in dementia were significantly correlated with performance on the Block Design (r = 0.68), MMSE (r = 0.56), and the Mental Control subtest in the WMS (r = 0.58). Stepwise regression analysis revealed that performance on the MMSE and the Block Design explain 53.8% of the variance in the CD scores. These findings indicate that low CD score by the Shulman method may be reflective of a constructional disability and general severity of dementia. CD is not so sensitive as the result of the original report when the patient group includes milder cases of AD. CD is, however, an efficient screening test for detecting and following the patients with dementia, especially combined with the MMSE.
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Affiliation(s)
- Y Nagahama
- Department of Geriatric Neurology, Shiga Medical Center
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33
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Mita M, Yoshikuni M, Nagahama Y, Maekawa M, Saito M, Saneyoshi M. Interaction of N1-substituted adenines with 1-methyladenine receptors of starfish oocytes in induction of maturation. Comp Biochem Physiol B Biochem Mol Biol 2001; 130:427-34. [PMID: 11567906 DOI: 10.1016/s1096-4959(01)00457-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Starfish oocytes are arrested naturally in the late G(2) phase of the first meiotic division. In response to the natural maturation-inducing hormone, 1-methyladenine (1-MA), oocytes undergo reinitiation of meiosis with germinal vesicle breakdown. We tested 10 newly synthesized N1-substituted adenines that are 1-MA analogues to analyze the interaction between 1-MA and its stereo-specific receptors on the oocyte plasma membranes of the starfish Asterina pectinifera. Among these analogues, 1-(beta-naphthylmethyl)adenine, 1-aminoadenine and 1-(p-nitrobenzyl)adenine played agonistic roles in the induction of oocyte maturation. 1-(o-Nitrobenzyl)adenine, 1-(m-nitrobenzyl)adenine, 1-phenethyladenine and 1-(p-nitrophenethyl)adenine had antagonist effects on 1-MA-induced oocyte maturation. These agonists and antagonists behaved competitively in the binding of [3H]1-MA to receptors in oocyte cortices. In contrast, 1-(alpha-naphthylmethyl)adenine, 1-(2,4-dinitrobenzyl)adenine and 1-(p-methoxybenzyl)adenine had no effects on oocyte maturation. Our results suggest that regional-specific sterical structures at the N1-site of adenine are important in the interaction between 1-MA and its receptors in oocytes. In addition, a negative charge at the N1-site of adenine is required for binding with the receptors.
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Affiliation(s)
- M Mita
- Teikyo Junior College, 6-31-1 Honmachi, Shibuya-ku, 151-0092, Tokyo, Japan.
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Nakahata S, Katsu Y, Mita K, Inoue K, Nagahama Y, Yamashita M. Biochemical identification of Xenopus Pumilio as a sequence-specific cyclin B1 mRNA-binding protein that physically interacts with a Nanos homolog, Xcat-2, and a cytoplasmic polyadenylation element-binding protein. J Biol Chem 2001; 276:20945-53. [PMID: 11283000 DOI: 10.1074/jbc.m010528200] [Citation(s) in RCA: 138] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Translational activation of dormant cyclin B1 mRNA stored in oocytes is a prerequisite for the initiation or promotion of oocyte maturation in many vertebrates. Using a monoclonal antibody against the domain highly homologous to that of Drosophila Pumilio, we have shown for the first time in any vertebrate that a homolog of Pumilio is expressed in Xenopus oocytes. This 137-kDa protein binds to the region including the sequence UGUA at nucleotides 1335-1338 in the 3'-untranslated region of cyclin B1 mRNA, which is close to but does not overlap the cytoplasmic polyadenylation elements (CPEs). Physical in vitro association of Xenopus Pumilio with a Xenopus homolog of Nanos (Xcat-2) was demonstrated by a protein pull-down assay. The results of immunoprecipitation experiments showed in vivo interaction between Xenopus Pumilio and CPE-binding protein (CPEB), a key regulator of translational repression and activation of mRNAs stored in oocytes. This evidence provides a new insight into the mechanism of translational regulation through the 3'-end of mRNA during oocyte maturation. These results also suggest the generality of the function of Pumilio as a translational regulator of dormant mRNAs in both invertebrates and vertebrates.
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Affiliation(s)
- S Nakahata
- Division of Biological Sciences, Graduate School of Science, Hokkaido University, Sapporo 060-0810, Japan
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35
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Miya F, Tokumoto M, Nagahama Y, Okida N, Ishikawa K, Tokumo T. Molecular cloning of ubiquitin-activating enzyme (E1) from Xenopus laevis. DNA Seq 2001; 11:349-52. [PMID: 11092751 DOI: 10.3109/10425170009033254] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
The Xenopus homologue to the ubiquitin-activating enzyme (E1) from a Xenopus ovary is described. The deduced amino acid sequence is highly homologous to E1 from other species.
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Affiliation(s)
- F Miya
- Department of Biology and Geosciences, Faculty of Science, Shizuoka University, Japan
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36
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Oba Y, Hirai T, Yoshiura Y, Kobayashi T, Nagahama Y. Fish gonadotropin and thyrotropin receptors: the evolution of glycoprotein hormone receptors in vertebrates. Comp Biochem Physiol B Biochem Mol Biol 2001; 129:441-8. [PMID: 11399478 DOI: 10.1016/s1096-4959(01)00374-8] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
We have cloned and characterized, for the first time in fish, two different gonadotropin receptors (GTHR) and a single thyrotropin receptor (TSHR) from amago salmon (Oncorhynchus rhodurus) and Nile tilapia (Oreochromis niloticus). Phylogenetic analyses and intron/exon structure suggest that the two GTHRs in fish are comparable to tetrapod follicle stimulating hormone and luteinizing hormone receptors. Temporal and spatial expression patterns, examined by Northern blot analysis and in situ hybridization, paralleled those seen in mammals and birds. Consequently, genetic and functional divergence of two GTHRs and TSHR probably occurred before the teleost and tetrapod split.
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Affiliation(s)
- Y Oba
- Laboratory of Reproductive Biology, National Institute for Basic Biology, 444-8585, Okazaki, Japan
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37
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Abstract
Two subtypes (alpha and beta) of androgen (AR) and progestogen receptors (PR) are present in the testis of Japanese eel (Anguilla japonica). Amino acid homology of the open reading frames between alpha and beta in AR or PR is approximately 40%, but the DNA- and ligand-binding domains show high homology between subtypes. Judging from these structures, alpha and beta are not isoforms derived from translational initiation at two in-phase ATG codons, alternative splicing, or tetraploidy. In transient transfection assays using a reporter construct containing a steroid-responsive promoter, each subtype showed its corresponding hormone-dependent transactivation. The ligand affinity for transactivation between AR and PR subtypes was similar for physiological ligands. Tissue distribution of both subtype mRNAs was different. Protein interaction between subtypes was demonstrated in vitro by GST pull-down assays. These results clearly indicate that two functional subtypes of AR and PR exist in eel. These findings will advance our understanding of the mechanisms underlying sex steroid signaling.
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Affiliation(s)
- T Ikeuchi
- Laboratory of Reproductive Biology, National Institute for Basic Biology, 444-8585, Okazaki, Japan
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Hirai T, Oba Y, Yoshikuni M, Nagahama Y, Mita M. cDNA cloning of GTH receptor family in starfish ovaries. ZYGOTE 2001; 8 Suppl 1:S54-5. [PMID: 11191311] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/19/2023]
Affiliation(s)
- T Hirai
- Department of Biosciences, Teikyo University of Science and Technology, Uenohara, Japan
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39
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Tanaka M, Kinoshita M, Kobayashi D, Nagahama Y. Establishment of medaka (Oryzias latipes) transgenic lines with the expression of green fluorescent protein fluorescence exclusively in germ cells: a useful model to monitor germ cells in a live vertebrate. Proc Natl Acad Sci U S A 2001; 98:2544-9. [PMID: 11226275 PMCID: PMC30174 DOI: 10.1073/pnas.041315498] [Citation(s) in RCA: 128] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2000] [Indexed: 11/18/2022] Open
Abstract
We have generated transgenic medaka (teleost, Oryzias latipes), which allow us to monitor germ cells by green fluorescent protein (GFP) fluorescence in live specimens. Two medaka strains, himedaka (orange-red variety) and inbred QurtE, were used. The transgenic lines were achieved by microinjection of a construct containing the putative promoter region and 3' region of the medaka vasa gene (olvas). The intensity of GFP fluorescence increases dramatically in primordial germ cells (PGCs) located in the ventrolateral region of the posterior intestine around stage 25 (the onset of blood circulation). Whole-mount in situ hybridization and monitoring of ectopically located cells by GFP fluorescence suggested that (i) the increase in zygotic olvas expression occurs after PGC specification and (ii) PGCs can maintain their cell characteristics ectopically after stages 20-25. Around the day of hatching, the QurtE strain clearly exhibits sexual dimorphisms in the number of GFP fluorescent germ cells, a finding consistent with the appearance of leucophores, a sex-specific marker of QurtE. The GFP expression persists throughout the later stages in the mature ovary and testis. Thus, these transgenic medaka represent a live vertebrate model to investigate how germ cells migrate to form sexually dimorphic gonads, as well as a potential assay system for environmental substances that may affect gonad development. The use of a transgenic construct as a selective marker to efficiently isolate germ-line-transmitting founders during embryogenesis is also discussed.
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Affiliation(s)
- M Tanaka
- Laboratory of Reproductive Biology, National Institute for Basic Biology, Okazaki 444-8585, Japan
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40
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Yamaguchi A, Yamashita M, Yoshikuni M, Nagahama Y. Identification and molecular cloning of germinal vesicle lamin B3 in goldfish (Carassius auratus) oocytes. Eur J Biochem 2001; 268:932-9. [PMID: 11179959 DOI: 10.1046/j.1432-1327.2001.01952.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
A bulk isolation method was developed to collect a large number of germinal vesicles (GV) from postvitellogenic oocytes of goldfish (Carassius auratus). Using this method, we obtained GV lamina which are resistant to high salt and nonionic detergent. 2D PAGE revealed that the goldfish GV lamina contained several spots with similar molecular masses (67 kDa) and slightly different neutral isoelectrofocusing values (pI 5.8-6.2). After trypsin digestion and extraction of a major spot (pI 6.1), the peptide was subjected to RP-HPLC and sequenced. A homology search identified this spot as a nuclear lamin. A cDNA encoding goldfish GV lamin was isolated by RT-PCR using degenerate primers designed from the GV lamin tryptic peptide sequence. The goldfish GV lamin cDNA encodes a predicted molecular mass of 67 455 Da with a pI of 5.84. Phylogenetic analysis indicates that the amino-acid sequence is most similar to Xenopus oocyte-specific GV lamin B3, but differs from somatic lamins (A, B1 or B2). In contrast to somatic lamins, neither goldfish nor Xenopus GV lamin contain conserved phosphorylation sites for nuclear transport, except the nuclear localization sequence. Therefore, we conclude that the goldfish oocyte GV is mainly comprised of GV-type lamin (the homolog of Xenopus lamin B3).
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Affiliation(s)
- A Yamaguchi
- Laboratory of Reproductive Biology, Department of Developmental Biology, National Institute for Basic Biology, Okazaki, Japan
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41
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Nagahama Y, Schick EC, Gaasch WH. Interval-dependent potentiation of left ventricular contractility is preserved in patients with atrial fibrillation and depressed ejection fraction. Am J Cardiol 2001; 87:342-6, A9. [PMID: 11165975 DOI: 10.1016/s0002-9149(00)01373-4] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Echocardiographic techniques were used to measure left ventricular isovolumic and ejection phase indexes of contractility in 54 patients with atrial fibrillation, and the relations between cycle lengths and contractility were compared in patients with normal and depressed ejection fractions. Data indicate that variations in contractility occur in a pattern that is consistent with postextrasystolic potentiation and that such interval-dependent potentiation is preserved in patients with atrial fibrillation and depressed ejection fraction.
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Affiliation(s)
- Y Nagahama
- Department of Cardiovascular Medicine, Lahey Clinic, Burlington, Massachusetts, USA
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42
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Somei M, Yamada F, Kurauchi T, Nagahama Y, Hasegawa M, Yamada K, Teranishi S, Sato H, Kaneko C. The chemistry of indoles. CIII. Simple syntheses of serotonin, N-methylserotonin, bufotenine, 5-methoxy-N-methyltryptamine, bufobutanoic acid, N-(indol-3-yl)methyl-5-methoxy-N-methyltryptamine, and lespedamine based on 1-hydroxyindole chemistry. Chem Pharm Bull (Tokyo) 2001; 49:87-96. [PMID: 11201232 DOI: 10.1248/cpb.49.87] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Application of regioselective nucleophilic substitution reactions of 1-hydroxytryptamines to novel and simple syntheses of serotonin (1a), N-methylserotonin (1b), bufotenine (1c), 5-methoxy-N-methyltryptamine (2a), bufobutanoic acid (3a), N-(indol-3-yl)methyl-5-methoxy-N-methyltryptamine (4), and lespedamine (5) are described. Effective syntheses of 5-benzyloxytryptamine and 1-methoxy-2-oxindoles are also reported.
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Affiliation(s)
- M Somei
- Faculty of Pharmaceutical Sciences, Kanazawa University, Japan.
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43
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Imahara J, Tokumoto M, Nagahama Y, Ishikawa K, Tokumoto T. Reconstitution of sperm nuclei of zebrafish (Danio rerio) in Xenopus egg extracts. Mar Biotechnol (NY) 2001; 3:53-57. [PMID: 14961390 DOI: 10.1007/s101260000047] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Cell-free extracts of Xenopus eggs cause cyclic change in permeabilized sperm nucleus, nuclear envelope breakdown, chromosome condensation, and reformation of nuclei. In this study, the ability of cell-free extracts to cause similar changes in zebrafish sperm was examined. When lysolecithin-treated sperm from zebrafish were incubated in Xenopus egg extracts, a series of changes in sperm nuclear morphology were observed periodically. These changes correlated with maturation-promoting factor (MPF) activity. Furthermore, sperm nuclei of zebrafish replicated DNA during reconstitution in Xenopus egg extracts. These results showed that cell-free extracts of Xenopus egg possess the ability to cause cell-cycle-dependent changes in zebrafish sperm, implying the possibility of generating transgenic zebrafish in a similar way to transgenic Xenopus.
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Affiliation(s)
- J Imahara
- Department of Biology and Geosciences, Faculty of Science, Shizuoka University, Shizuoka 422-8529, Japan
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44
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Matsuda M, Kawato N, Asakawa S, Shimizu N, Nagahama Y, Hamaguchi S, Sakaizumi M, Hori H. Construction of a BAC library derived from the inbred Hd-rR strain of the teleost fish, Oryzias latipes. Genes Genet Syst 2001; 76:61-3. [PMID: 11376553 DOI: 10.1266/ggs.76.61] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
A large insert genomic bacterial artificial chromosome (BAC) library was constructed from the inbred Hd-rR strain of the medaka, Oryzias latipes. Approximately 92,000 clones were gridded on high-density replica filters. Insert analysis of randomly selected clones indicated a mean insert size of 210 kb and predicted a 24 times coverage of the medaka genome. The library was hybridized with a single locus DNA fragment, and the resulting positive clones were characterized and shown to be compatible with a 24-fold redundant library. This first large insert genomic library of the medaka should increase the speed of genomic analyses for this fish species.
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Affiliation(s)
- M Matsuda
- Laboratory of Reproductive Biology, National Institute for Basic Biology, Okazaki, Japan
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45
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Nagahama Y, Okada T, Katsumi Y, Hayashi T, Yamauchi H, Oyanagi C, Konishi J, Fukuyama H, Shibasaki H. Dissociable mechanisms of attentional control within the human prefrontal cortex. Cereb Cortex 2001; 11:85-92. [PMID: 11113037 DOI: 10.1093/cercor/11.1.85] [Citation(s) in RCA: 176] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Neuropsychological tests that require shifting an attentional set, such as the Wisconsin Card Sorting Test, are sensitive to frontal lobe damage. Although little information is available for humans, an animal experiment suggested that different regions of the prefrontal cortex may contribute to set shifting behavior at different levels of processing. Behavioral studies also suggest that set shifting trials are more time consuming than non-set shifting trials (i.e. switch cost) and that this may be underpinned by differences at the neural level. We determined whether there were differential neural responses associated with two different levels of shifting behavior, that of reversal of stimulus-response associations within a perceptual dimension or that of shifting an attentional set between different perceptual dimensions. Neural activity in the antero-dorsal prefrontal cortex increased only in attentional set shifting, in which switch costs were significant. Activity in the postero-ventral prefrontal cortex increased not only in set shifting but also in reversing stimulus-response associations, in which switch costs were absent. We conclude that these distinct regions in the human prefrontal cortex provide different levels of attention control in response selection. Thus, the antero-dorsal prefrontal cortex may be critical for higher order control of attention, i.e. attentional set shifting, whereas the postero-ventral area may be related to a lower level of shift, i.e. reorganizing stimulus-response associations.
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Affiliation(s)
- Y Nagahama
- Department of Brain Pathophysiology, Faculty of Medicine, Kyoto University, 54 Shogoin Kawahara-cho, Sakyo, Kyoto 606-8507, Japan
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46
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Liu S, Govoroun M, D'Cotta H, Ricordel MJ, Lareyre JJ, McMeel OM, Smith T, Nagahama Y, Guiguen Y. Expression of cytochrome P450(11beta) (11beta-hydroxylase) gene during gonadal sex differentiation and spermatogenesis in rainbow trout, Oncorhynchus mykiss. J Steroid Biochem Mol Biol 2000; 75:291-8. [PMID: 11282285 DOI: 10.1016/s0960-0760(00)00186-2] [Citation(s) in RCA: 60] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Androgens and especially 11-oxygenated androgens are known to be potent masculinizing steroids in fish. As a first step to study their physiological implication in gonadal sex differentiation in fish, we cloned a testicular cytochrome P450(11beta) (11beta-hydroxylase) cDNA in the rainbow trout, Oncorhynchus mykiss. We isolated a 1882 bp P450(11beta) cDNA (rt11betaH2, AF217273) which contains an open reading frame encoding a 552 putative amino acids protein. This sequence was highly homologous (98% in nucleotides and 96.5% in amino acids) to another rainbow trout P450(11beta) sequence (AF179894) and also to a Japanese eel P450(11beta) (68% in amino acids). Northern blot analysis detected a single transcript of 2 kb which was highly expressed in the testis (stage II) and to a lesser degree in the anterior kidney (containing the interrenal tissue). No signal was detected in the posterior kidney, brain, liver, skin, intestine and heart. In the testis this transcript was highly expressed at the beginning of spermatogenesis (stages I and II), followed by a decrease during late spermatogenesis (stages III to V). By semi-quantitative reverse transcription polymerase chain reaction, P450(11beta) expression during gonadal differentiation was estimated to be at least 100 times higher in male than in female gonads. This difference was first detected at 55 days post-fertilization (dpf), i.e. 3 weeks before the first sign of histological sex differentiation, and was sustained long after differentiation (127 dpf). Specific P450(11beta) gene expression was also demonstrated before testis differentiation (around 50 dpf) using virtual Northern blot, with no expression detected in female differentiating gonads. From these results, and also based on the already known actions of 11-oxygenated androgens in testicular differentiation in fish, it is now suggested that P450(11beta) gene expression is a key factor for the testicular differentiation in rainbow trout.
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Affiliation(s)
- S Liu
- Station INRA SCRIBE, Equipe Sexualite et Reproduction, Campus de Beaulieu, 35042 Cedex, Rennes, France
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Kobayashi T, Kajiura-Kobayashi H, Nagahama Y. Differential expression of vasa homologue gene in the germ cells during oogenesis and spermatogenesis in a teleost fish, tilapia, Oreochromis niloticus. Mech Dev 2000; 99:139-42. [PMID: 11091081 DOI: 10.1016/s0925-4773(00)00464-0] [Citation(s) in RCA: 135] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Vas (a Drosophila vasa homologue) gene expression pattern in germ cells during oogenesis and spermatogenesis was examined using all genetic females and males of a teleost fish, tilapia. Primordial germ cells (PGC) reach the gonadal anlagen 3 days after hatching (7 days after fertilization), the time when the gonadal anlagen was first formed. Prior to meiosis, no differences in vas RNA are observed in male and female germ cells. In the ovary, vas is expressed strongly in oogonia to diplotene oocytes and becomes localized as patches in auxocytes and then strong signals are uniformly distributed in the cytoplasm of previtellogenic oocytes, followed by a decrease from vitellogenic to postvitellogenic oocytes. In the testis, vas signals are strong in spermatogonia and decrease in early primary spermatocytes. No vas RNA expression is evident in either diplotene primary spermatocytes, secondary spermatocytes, spermatids or spermatozoa. The observed differences in vas RNA expression suggest a differential function of vas in the regulation of meiotic progression of female and male germ cells.
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Affiliation(s)
- T Kobayashi
- Department of Developmental Biology, National Institute for Basic Biology, 444-8585, Okazaki, Japan
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48
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Matsuda M, Nagahama Y. [Construction of a Medaka BAC library]. Tanpakushitsu Kakusan Koso 2000; 45:2880-5. [PMID: 11187792] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/19/2023]
Affiliation(s)
- M Matsuda
- Laboratory of Reproductive Biology, National Institute for Basic Biology, Myodaiji-cho, Okazaki, Aichi 444-8585, Japan.
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49
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Yamauchi H, Fukuyama H, Nagahama Y, Katsumi Y, Hayashi T, Oyanagi C, Konishi J, Shio H. Comparison of the pattern of atrophy of the corpus callosum in frontotemporal dementia, progressive supranuclear palsy, and Alzheimer's disease. J Neurol Neurosurg Psychiatry 2000; 69:623-9. [PMID: 11032614 PMCID: PMC1763404 DOI: 10.1136/jnnp.69.5.623] [Citation(s) in RCA: 72] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
OBJECTIVES The loss of the neurons in layer 3, one of the groups of cortical neurons most vulnerable in various degenerative brain diseases, results in axonal degeneration leading to atrophy of the corpus callosum. Previous studies showed callosal atrophy in three degenerative dementias: frontotemporal dementia (FTD), progressive supranuclear palsy (PSP), and Alzheimer's disease (AD). However, it is unclear whether a characteristic pattern of atrophy is present in each. The objective of this study was to investigate whether the pattern of the callosal atrophy was different among patients with FTD, PSP, or early onset AD. METHODS Eleven patients with FTD, nine patients with PSP, 16 patients with early onset AD, and 23 normal controls, all age and sex matched, were studied using MRI. The ratios of midsagittal corpus callosum areas to the midline internal skull surface area on T1 weighted images were analyzed. The corpus callosum was divided into quarters: the anterior, middle-anterior, middle-posterior, and posterior portions. RESULTS Compared with controls, all three patient groups had significantly decreased total callosal/skull area ratio. An analysis of covariance adjusted for the total callosal area/skull area ratio showed that the anterior quarter callosal/skull area ratio in FTD, the middle-anterior quarter area ratio in PSP, and the posterior quarter area ratio in AD were significantly smaller than those in the other three groups. CONCLUSION Although atrophy of the corpus callosum is not specific to any degenerative dementia, the patterns of the atrophy are different among patients with FTD, PSP, or early onset AD. Differential patterns of callosal atrophy might reflect characteristic patterns of neocortical involvement in each degenerative dementia.
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Affiliation(s)
- H Yamauchi
- Department of Neurology, Faculty of Medicine, Kyoto University, Kyoto, Japan.
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50
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Takehana K, Sugiura T, Nagahama Y, Inada M, Iwasaka T. Diastolic time during weight carrying exercise in patients with myocardial infarction. Cardiology 2000; 89:68-72. [PMID: 9452160 DOI: 10.1159/000006745] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Cardiovascular responses to static-dynamic exercises were studied in 27 patients with recent myocardial infarction. Patients with ischemic electrocardiographic changes at peak weight carrying exercise (group 1 = 8 patients) had a significantly larger left ventricular end-diastolic volume than those without (group 2 = 19 patients). A higher tension time index and shortening of diastolic time/min was observed in group 1 compared to group 2 during weight carrying. Thus, in addition to the increased myocardial oxygen demand, shortening of the diastolic perfusion time was observed during static-dynamic exercise in patients with dilated heart after myocardial infarction.
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Affiliation(s)
- K Takehana
- Second Department of Internal Medicine, Kansai Medical University, Osaka, Japan
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