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Seale AP, Malintha GHT, Celino-Brady FT, Head T, Belcaid M, Yamaguchi Y, Lerner DT, Baltzegar DA, Borski RJ, Stoytcheva ZR, Breves JP. Transcriptional regulation of prolactin in a euryhaline teleost: Characterisation of gene promoters through in silico and transcriptome analyses. J Neuroendocrinol 2020; 32:e12905. [PMID: 32996203 PMCID: PMC8612711 DOI: 10.1111/jne.12905] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/08/2020] [Revised: 07/31/2020] [Accepted: 08/26/2020] [Indexed: 12/20/2022]
Abstract
The sensitivity of prolactin (Prl) cells of the Mozambique tilapia (Oreochromis mossambicus) pituitary to variations in extracellular osmolality enables investigations into how osmoreception underlies patterns of hormone secretion. Through the actions of their main secretory products, Prl cells play a key role in supporting hydromineral balance of fishes by controlling the major osmoregulatory organs (ie, gill, intestine and kidney). The release of Prl from isolated cells of the rostral pars distalis (RPD) occurs in direct response to physiologically relevant reductions in extracellular osmolality. Although the particular signal transduction pathways that link osmotic conditions to Prl secretion have been identified, the processes that underlie hyposmotic induction of prl gene expression remain unknown. In this short review, we describe two distinct tilapia gene loci that encode Prl177 and Prl188 . From our in silico analyses of prl177 and prl188 promoter regions (approximately 1000 bp) and a transcriptome analysis of RPDs from fresh water (FW)- and seawater (SW)-acclimated tilapia, we propose a working model for how multiple transcription factors link osmoreceptive processes with adaptive patterns of prl177 and prl188 gene expression. We confirmed via RNA-sequencing and a quantitative polymerase chain reaction that multiple transcription factors emerging as predicted regulators of prl gene expression are expressed in the RPD of tilapia. In particular, gene transcripts encoding pou1f1, stat3, creb3l1, pbxip1a and stat1a were highly expressed; creb3l1, pbxip1a and stat1a were elevated in fish acclimated to SW vs FW. Combined, our in silico and transcriptome analyses set a path for resolving how adaptive patterns of Prl secretion are achieved via the integration of osmoreceptive processes with the control of prl gene transcription.
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Affiliation(s)
- Andre P. Seale
- Department of Human Nutrition, Food and Animal Sciences, University of Hawai’i at Mānoa, Honolulu, HI, USA
| | | | - Fritzie T. Celino-Brady
- Department of Human Nutrition, Food and Animal Sciences, University of Hawai’i at Mānoa, Honolulu, HI, USA
| | - Tony Head
- Department of Human Nutrition, Food and Animal Sciences, University of Hawai’i at Mānoa, Honolulu, HI, USA
| | - Mahdi Belcaid
- Hawai’i Institute of Marine Biology, University of Hawai’i at Mānoa, Kaneohe, HI, USA
| | - Yoko Yamaguchi
- Institute of Agricultural and Life Sciences, Academic Assembly, Shimane University, Matsue, Japan
| | - Darren T. Lerner
- University of Hawai’i Sea Grant College Program, University of Hawai’i at Mānoa, Honolulu, HI, USA
| | - David A. Baltzegar
- Genomic Sciences Laboratory, Office of Research and Innovation, North Carolina State University, Raleigh, NC, USA
| | - Russell J. Borski
- Department of Biological Sciences, North Carolina State University, Raleigh, NC, USA
| | - Zoia R. Stoytcheva
- Department of Human Nutrition, Food and Animal Sciences, University of Hawai’i at Mānoa, Honolulu, HI, USA
| | - Jason P. Breves
- Department of Biology, Skidmore College, Saratoga Springs, NY, USA
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Rhee JS, Kim RO, Seo JS, Lee J, Lee YM, Lee JS. Effects of salinity and endocrine-disrupting chemicals on expression of prolactin and prolactin receptor genes in the euryhaline hermaphroditic fish, Kryptolebias marmoratus. Comp Biochem Physiol C Toxicol Pharmacol 2010; 152:413-23. [PMID: 20620225 DOI: 10.1016/j.cbpc.2010.07.001] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/06/2009] [Revised: 07/02/2010] [Accepted: 07/04/2010] [Indexed: 11/15/2022]
Abstract
Prolactin plays an essential role in ion uptake as well as reduction in ion and water permeability of osmoregulatory surfaces in euryhaline fish. Kryptolebias marmoratus is a euryhaline fish with unique internal self-fertilization. In order to understand the effect of different salinities and environmental endocrine-disrupting chemicals (EDCs) on the regulation of prolactin (PRL) and prolactin receptor (PRLR) genes, the full-length sequences of PRL and two PRLR genes were cloned from K. marmoratus. The expression pattern of K. marmoratus PRL (Km-PRL) and PRLR (Km-PRLR1, Km-PRLR2) mRNAs was analyzed in different developmental stages (2dpf to 5h post-hatching) and tissues of hermaphrodite fish. To investigate the effects of salinity changes and EDC exposure, the mRNA expression pattern of PRL, PRLR1 and PRLR2 was analyzed in exposed fish. The Km-PRL mRNA in the hermaphrodite was predominantly expressed in the brain/pituitary, the Km-PRLR1 mRNA was highly expressed in the intestine, while the Km-PRLR2 mRNA was intensively expressed in the gills. The expression of the Km-PRL mRNA generally increased from stage 1 (2 dpf) to stage 3 (12 dpf) in a developmental, stage-dependent manner. It decreased in stage 4 (12 dpf) and the hatching stage (stage 5). Km-PRLR1 and Km-PRLR2 mRNAs showed a gradual increase in expression from stage 1 (2 dpf) to stage 4 (12 dpf) and decreased by stage 5 (5 h post-hatching). Also, both mRNAs of PRLR showed a different expression pattern after exposure to different salinity concentrations (0, 33, and 50 ppt) in juvenile fish. The expression of PRL mRNA was upregulated at 0 ppt, but was downregulated at a moderately higher salinity concentration (33 to 50 ppt). The Km-PRLR1 mRNA showed upregulation at freshwater stress (0 ppt) compared to other concentrations of salinity (33 ppt to 50 ppt). The Km-PRLR2 mRNA was marginally upregulated at freshwater stress (0 ppt), but was downregulated at a higher salinity concentration (50 ppt) and showed no significant change in expression at 33 ppt salinity. Interestingly, both mRNAs showed upregulation in the brain (e.g. Km-PRL) and intestine (e.g. Km-PRLR1) after EDC exposure. These findings suggested that Km-PRL and two Km-PRLR mRNAs would be useful in analyzing the effect of different salinities as well as the modulatory effect of EDC exposure on these gene expressions in K. marmoratus.
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Affiliation(s)
- Jae-Sung Rhee
- Department of Molecular and Environmental Bioscience, Graduate School, Hanyang University, Seoul 133-791, South Korea
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Agnèse JF, Adépo-Gourène B, Nyingi D. Functional microsatellite and possible selective sweep in natural populations of the black-chinned tilapia Sarotherodon melanotheron (Teleostei, Cichlidae). Mar Genomics 2008; 1:103-7. [PMID: 21798160 DOI: 10.1016/j.margen.2008.10.004] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2008] [Accepted: 10/23/2008] [Indexed: 11/25/2022]
Abstract
The Prolactin I (PrlI) gene is a key locus involved in fish osmotic regulation. Two microsatellites, PrlI GT and PrlI AC, are present in the promoter region of this gene in tilapias. One of these microsatellite is associated to PrlI gene expression and growth rate. Aquaria reared individuals homozygous for long microsatellite alleles at the PrlI AC locus expressed less PrlI in fresh water than fishes with other genotypes. To assess the occurrence of selection acting on these microsatellites we carried out a survey of their variability compared with four others microsatellites in natural populations. Samples of two tilapia species were studied, Oreochromis niloticus (6 samples) a typically freshwater species inhabiting osmotically stable environments and Sarotherodon melanotheron (5 samples) a brackish water species obliged and able to adapt very rapidly to any salinity changes. For both species the different populations studied exhibited a high amount of differentiation (all F(st) value were statistically significant) at every loci. Only one locus, PrlI AC, was monomorphic for the same allele in all S. melanotheron populations. We have hypothesized that this outlier locus with its unique allele could have experienced a selective sweep that took place in the early stages of the species origin. S. melanotheron represents an example of adaptation (to fluctuant salinity environment) acting indirectly on gene product through its promoter.
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Affiliation(s)
- Jean-François Agnèse
- Laboratoire Biologie Intégrative, UM2 - IFREMER - CNRS UMR 5554, Université de Montpellier II, cc 63 - Place E Bataillon F-34095 Montpellier Cedex 5, France; Institut de Recherche pour le Développement, 213 rue La Fayette, 75480, Paris CEDEX 10, France
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Boutet I, Lorin-Nebel C, De Lorgeril J, Guinand B. Molecular characterisation of prolactin and analysis of extrapituitary expression in the European sea bass Dicentrarchus labrax under various salinity conditions. COMPARATIVE BIOCHEMISTRY AND PHYSIOLOGY D-GENOMICS & PROTEOMICS 2006; 2:74-83. [PMID: 20483280 DOI: 10.1016/j.cbd.2006.12.002] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/15/2006] [Revised: 12/04/2006] [Accepted: 12/04/2006] [Indexed: 10/23/2022]
Abstract
Although prolactin has been demonstrated to be the main hormone involved in adaptation to dilute media in several freshwater teleosts, few studies have been conducted in marine teleosts. In the Mediterranean, the sea bass Dicentrarchus labrax inhabits environments ranging from the open sea to coastal lagoons, where salinity varies greatly. We characterised the prolactin (prl) gene and analysed its expression in two organs (gill and intestine) in D. labrax acclimated to either freshwater or seawater. A 2819 bp long sequence encompassing the prl gene and a part (282 bp) of the promoter were identified, and these comprised 5 coding exons separated by 4 introns. Prolactin was similarly expressed in fresh- and seawater adapted fish, although expression in gills was significantly greater than in the intestine. Nonetheless, individuals unable to successfully regulate osmotic balance in freshwater presented overall low expression rates. Results are discussed according to the mechanism of sea bass adaptation in the wild and to their life cycle between open sea and lagoons. Finally, a phylogenetic analysis indicated that teleosts are not branched according to their life-history features (e.g. seawater vs. freshwater habitats), and no signature of positive selection was detected across the phylogeny of the prl gene in teleosts.
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Affiliation(s)
- I Boutet
- Laboratoire Génome Populations Interaction Adaptation, UMR CNRS IFREMER 5171, Université de Montpellier 2, Place Eugène Bataillon, 34095 Montpellier cedex 5, France
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Moriyama S, Oda M, Takahashi A, Sower SA, Kawauchi H. Genomic structure of the sea lamprey growth hormone-encoding gene. Gen Comp Endocrinol 2006; 148:33-40. [PMID: 16288756 DOI: 10.1016/j.ygcen.2005.09.023] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/13/2005] [Accepted: 09/21/2005] [Indexed: 12/01/2022]
Abstract
Growth hormone (GH) belongs to a family of pituitary hormones together with prolactin and somatolactin. In our previous study, GH and its cDNA were identified in the pituitary gland of the sea lamprey, Petromyzon marinus, an extant representative of the most ancient class of vertebrates, and isolated GH stimulated expression of insulin-like growth factor in the liver. The evidence suggests that GH is the ancestral hormone in the molecular evolution of the GH/PRL/SL family and that the endocrine mechanism for growth stimulation was established at an early stage in the evolution of vertebrates. To further understand the molecular evolution of the GH/PRL/SL gene family, we report the genomic structure of sea lamprey GH including its 5'-flanking region, being cloned by PCR using specific primers prepared from its cDNA. The sea lamprey GH gene consists of 13,604 bp, making it the largest of all the GH genes. The 5'-flanking region within 697 bp contains consensus sequences for a TATA box, two Pit-1/GHF-1, three TRE, and a CRE. The sea lamprey GH gene consists of five exons and four introns, the same as in mammals, birds, and teleosts such as cypriniforms and siluriforms with the exception of some teleosts such as salmoniforms, percififorms, and tetradontiforms, in which there is an additional intron in the 5th exon. The 5-exon-type gene organization might reflect the structure of the ancestral gene for the GH/PRL/SL gene family.
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Affiliation(s)
- Shunsuke Moriyama
- Laboratory of Molecular Endocrinology, School of Fisheries Sciences, Kitasato University, Sanriku, Iwate 022-0101, Japan.
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Kawauchi H, Sower SA. The dawn and evolution of hormones in the adenohypophysis. Gen Comp Endocrinol 2006; 148:3-14. [PMID: 16356498 DOI: 10.1016/j.ygcen.2005.10.011] [Citation(s) in RCA: 154] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/09/2005] [Revised: 10/26/2005] [Accepted: 10/26/2005] [Indexed: 01/10/2023]
Abstract
The adenohypophysial hormones have been believed to have evolved from several ancestral genes by duplication followed by evolutionary divergence. To understand the origin and evolution of the endocrine systems in vertebrates, we have characterized adenohypophysial hormones in an agnathan, the sea lamprey Petromyzon marinus. In gnathostomes, adrenocorticotropin (ACTH) and melanotropin (MSH) together with beta-endorphins (beta-END) are encoded in a single gene, designated as proopiomelanocortin (POMC), however in sea lamprey, ACTH and MSH are encoded in two distinct genes, proopoicortin (POC) gene and proopiomelanotropin (POM) gene, respectively. The POC and POM genes are expressed specifically in the rostral pars distalis (RPD) and the pars intermedia (PI), respectively. Consequently, the final products from both tissues are the same in all vertebrates, i.e., ACTH from the PD and MSH from the PI. The POMC gene might have been established in the early stages of invertebrate evolution by internal gene duplication of the MSH domains. The ancestral gene might be then inherited in lobe-finned fish and tetrapods, while internal duplication and deletion of MSH domains as well as duplication of whole POMC gene took place in lamprey and gnathostome fish. Sea lamprey growth hormone (GH) is expressed in the cells of the dorsal half of the proximal pars distalis (PPD) and stimulates the expression of an insulin-like growth factor (IGF) gene in the liver as in other vertebrates. Its gene consists of 5 exons and 4 introns spanning 13.6 kb, which is the largest gene among known GH genes. GH appears to be the only member of the GH family in the sea lamprey, which suggests that GH is the ancestral hormone of the GH family that originated first in the molecular evolution of the GH family in vertebrates and later, probably during the early evolution of gnathostomes. The other member of the gene family, PRL and SL, appeared by gene duplication. A beta-chain cDNA belonging to the gonadotropin (GTH) and thyrotropin (TSH) family was cloned. It is expressed in cells of the ventral half of PPD. Since the expression of this gene is stimulated by lamprey gonadotropin-releasing hormone, it was assigned to be a GTHbeta. This GTHbeta is far removed from beta-subunits of LH, FSH, and TSH in an unrooted tree derived from phylogenetic analysis, and takes a position as an out group, suggesting that lampreys have a single GTH gene, which duplicated after the agnathans and prior to the evolution of gnathostomes to give rise to LH and FSH.
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Affiliation(s)
- Hiroshi Kawauchi
- Laboratory of Molecular Endocrinology, School of Fisheries Sciences, Kitasato University, Sanriku, Iwate 022-0101, Japan.
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Astola A, Ortiz M, Calduch-Giner JA, Pérez-Sánchez J, Valdivia MM. Isolation of Sparus auratus prolactin gene and activity of the cis-acting regulatory elements. Gen Comp Endocrinol 2003; 134:57-61. [PMID: 13129503 DOI: 10.1016/s0016-6480(03)00214-4] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
A sea bream prolactin (sbPRL) gene was isolated using a prolactin cDNA fragment, generated by PCR as a probe. The gene analyzed comprises 3.5 kb of DNA containing five exons as described previously for other fish PRL genes. Analysis of 1.0 kb of the proximal promoter sequence reveals a consensus TATAA box, up to seven (A/T)3NCAT consensus motifs for binding of the pituitary-specific factor Pit-1 and putative CREB and GATA binding sites. CHO culture cells co-transfected with a sbPRL promoter sequence and a sea bream Pit-1 cDNA expression plasmid showed expression of a linked luciferase reporter gene. Transient expression experiments with 5'-delection mutants reveals at least three regulatory regions on the sbPRL gene, two with a stimulatory effect on transcription and one with apparent inhibitory effect. From a comparative point of view, this study of PRL gene in Sparus auratus, correlates well with those previously published on tilapia and rainbow trout. The molecular data reported will be useful for comparative analysis of gene regulation in the GH/PRL gene family in teleosts.
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Affiliation(s)
- Antonio Astola
- Departamento de Bioquímica y Biología Molecular, Facultad de Ciencias, Universidad de Cádiz, Puerto Real, Cádiz 11510, Spain
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Streelman JT, Kocher TD. Microsatellite variation associated with prolactin expression and growth of salt-challenged tilapia. Physiol Genomics 2002; 9:1-4. [PMID: 11948285 DOI: 10.1152/physiolgenomics.00105.2001] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Biologists have long argued that runs of alternating purines and pyrimidines could form alternative DNA structures, which might regulate transcription. Here, we report that simple sequence repeat polymorphisms in the tilapia prolactin 1 (prl 1) promoter are associated with differences in prl 1 gene expression and the growth response of salt-challenged fishes. Individuals homozygous for long microsatellite alleles express less prl 1 in fresh water but more prl 1 in half-seawater than fishes with other genotypes. Our work provides the first in vivo evidence that differences in microsatellite length among individuals may indeed affect gene expression and that variance in expression has concomitant physiological consequences. These results suggest that dinucleotide microsatellites represent an under-appreciated source of genetic variation for regulatory evolution.
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Affiliation(s)
- J T Streelman
- Hubbard Center for Genome Studies, University of New Hampshire, Durham, New Hampshire 03824, USA.
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Molina A, Iyengar A, Marins LF, Biemar F, Hanley S, Maclean N, Smith TJ, Martial JA, Muller M. Gene structure and promoter function of a teleost ribosomal protein: a tilapia (Oreochromis mossambicus) L18 gene. BIOCHIMICA ET BIOPHYSICA ACTA 2001; 1520:195-202. [PMID: 11566355 DOI: 10.1016/s0167-4781(01)00272-x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
We have cloned and characterized a tilapia (Oreochromis mossambicus) L18 ribosomal protein gene, including the complete transcribed region and 488 bp of upstream regulatory sequences. We have also isolated two L18 cDNAs from another tilapia (Oreochromis niloticus) with a few conservative nucleotide differences. Our results suggest the presence of two genes in both species. Reporter constructs were tested for transient expression in CV1 cells and in microinjected zebrafish and tilapia embryos. The tilapia L18 promoter was able to drive expression of the reporter gene in all three experiments, with no apparent preference for a particular tissue. The tilapia L18 promoter is therefore likely to be a powerful tool to drive tissue-independent gene expression in fish.
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Affiliation(s)
- A Molina
- Laboratoire de Biologie Moléculaire et de Génie Génétique, Université de Liège, Institut de Chemie B6, Sart-Tilman, Belgium
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Hwang IT, Lee YH, Moon BC, Ahn KY, Lee SW, Chun JY. Identification and characterization of a new member of the placental prolactin-like protein-C (PLP-C) subfamily, PLP-Cbeta. Endocrinology 2000; 141:3343-52. [PMID: 10965907 DOI: 10.1210/endo.141.9.7635] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
We have isolated a complementary DNA (cDNA) clone that encodes a new member of the PRL-like protein-C (PLP-C) subfamily of the PRL gene family. The clone was amplified from a 13.5-day-old mouse conceptus cDNA library by PCR using primers based on conserved regions of PLP-C sequences. The full-length cDNA encodes a predicted protein of 241 residues, which contains a putative signal sequence and 2 putative N-linked glycosylation sites. The predicted protein shares 55-66% amino acid identity with mouse PLP-Calpha and rat PLP-D, PLP-H, PLP-Cv, and PLP-C and also contains 6 homologously positioned cysteine residues. Thus, we named this protein PLP-Cbeta for consistency. We have also isolated rat PLP-Cbeta from rat placenta cDNA library. Surprisingly, two messenger RNA (mRNA) isoforms of rat PLP-Cbeta were isolated: one mRNA (rPLP-Cbeta) encodes a 241-amino acid product, but another mRNA (rPLP-Cbetadelta39) lacks 39 bases that encode for a region rich in aromatic amino acids. The 39-bp region corresponds to exon 3 of other PLP-C subfamily members, such as PLP-Calpha, PLP-Cv, and d/tPRP. It suggests that the two isoforms are probably generated by an alternative splicing from a single gene. RT-PCR analysis revealed that the rPLP-Cbeta form was dominantly expressed in placenta, although both isoforms are coexpressed during placentation. The mouse PLP-Cbeta mRNA expression, which was specific to the placenta, was first detected by Northern analysis on embryonic day 11.5 (E 11.5) and persisted until birth. However, in situ hybridization analysis revealed mPLP-Cbeta expression on E 10.5 in specific trophoblast subsets, such as giant cells and spongiotrophoblast cells. mPLP-Cbeta mRNA was detected in the labyrinthine zone on E 18.5, suggesting that spongiotrophoblast cells had penetrated the labyrinthotrophoblast zone. Consistent with the observed expression in trophoblast giant cells, PLP-Cbeta expression was also detected in in vitro differentiated Rcho-1 cells, which express the trophoblast giant cell phenotype. In summary, overall high amino acid identity (79%), the locations of cysteine residues, and consensus sites for N-linked glycosylation between mouse and rat PLP-Cbeta clearly indicate that PLP-Cbeta is a bona fide member of the PLP-C subfamily. The conservation between mouse and rat, the presence of alternative isoforms, and the pattern of expression during gestation suggest the biological significance of PLP-Cbeta during pregnancy.
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Affiliation(s)
- I T Hwang
- Kumho Life and Environmental Science Laboratory, Kwangju, Korea
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McConnell SK, Beynon C, Leamon J, Skibinski DO. Microsatellite marker based genetic linkage maps of Oreochromis aureus and O. niloticus (Cichlidae): extensive linkage group segment homologies revealed. Anim Genet 2000; 31:214-8. [PMID: 10895314 DOI: 10.1046/j.1365-2052.2000.00631.x] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Partial genetic linkage maps, based on microsatellite markers, were constructed for two tilapia species, Oreochromis aureus and Oreochromis niloticus using an interspecific backcross population. The linkage map for O. aureus comprised 28 markers on 10 linkage groups and covered 212.8 CM. Nine markers were mapped to four linkage groups on an O. niloticus female linkage map covering 40.6 CM. Results revealed a high degree of conservation of synteny between the linkage groups defined in O. aureus and the previously published genetic linkage map of O. niloticus.
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Affiliation(s)
- S K McConnell
- School of Biological Sciences, University of Wales Swansea, UK
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Molina A, Biemar F, Müller F, Iyengar A, Prunet P, Maclean N, Martial JA, Muller M. Cloning and expression analysis of an inducible HSP70 gene from tilapia fish. FEBS Lett 2000; 474:5-10. [PMID: 10828441 DOI: 10.1016/s0014-5793(00)01538-6] [Citation(s) in RCA: 58] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/16/2022]
Abstract
We isolated and characterized the tilapia (Oreochromis mossambicus) HSP70 gene, highly homologous to other HSP70 genes. A dramatic increase of tilapia HSP70 mRNA levels was observed after heat shock of whole animals in all organs tested. Reporter constructs were tested for transient expression in carp cells and in microinjected zebrafish embryos. The entire isolated regulatory region (-851/+157) was able to mediate heat shock inducible expression of the reporter gene, with no preference for a particular tissue. Our studies represent the first transcriptional analysis of a HSP70 promoter from fish, revealing a powerful tool to direct controlled, tissue-independent gene expression in fish.
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Affiliation(s)
- A Molina
- Laboratoire de Biologie Moléculaire et Génie Génétique, Université de Liège, Institut de Chimie B6, B-40000 Sart-Tilman, Belgium, UK
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13
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Sekkali B, Brim H, Muller M, Argenton F, Bortolussi M, Colombo L, Belayew A, Martial JA. Structure and functional analysis of a tilapia (Oreochromis mossambicus) growth hormone gene: activation and repression by pituitary transcription factor Pit-1. DNA Cell Biol 1999; 18:489-502. [PMID: 10390158 DOI: 10.1089/104454999315213] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
A gene encoding the Tilapia mossambica (Oreochromis mossambicus) growth hormone (tiGH) was isolated and sequenced. The gene spans 5.6 kb, including 3.7 kb of 5' and 0.2 kb of 3' flanking sequences and a 1.7-kb transcription unit comprised of six exons and five introns. The gene and the 5' flanking region contain several potential binding sites for Pit-1, a key transcription activator of mammalian GH genes. One of these (-57/-42) is highly conserved in fish GH genes. It activates transcription in pituitary cells and binds Pit-1. Transfection of luciferase reporter plasmids containing either the -3602/+19 tiGH sequence or one of its 5' deletion mutants (-2863/, -1292/, and -463/+19) resulted in strong activity in Pit-1-producing rat pituitary GC cells. A dose-dependent activation of the tiGH promoter was achieved in nonpituitary fish EPC and monkey COS cells cotransfected with a rat Pit-1 expression vector, demonstrating the crucial role played by Pit-1 as an activator of the tiGH gene. Fusion of the tiGH promoter with the beta-galactosidase gene led to transient expression specifically in the nervous system of microinjected zebrafish embryos. The activity of the tiGH promoter in GC and EPC cells was strongly repressed by extending its 3' end from +19 to +40, a sequence in which a Pit-1-binding site was identified using gel retardation assays. Point mutations of the site that suppressed Pit-1 binding in vitro restored full tiGH promoter activity. Thus, a Pit-1-binding site located in the 5' untranslated region mediates Pit-1-dependent repression of the tiGH gene.
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Affiliation(s)
- B Sekkali
- Laboratoire de Biologie Moléculaire et de Génie Génétique, Université de Liège, Institut de Chimie B6, Sart-Tilman, Belgium
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Poncelet AC, Levavi-Sivan B, Muller M, Yaron Z, Martial JA, Belayew A. The tilapia prolactin I gene: evolutionary conservation of the regulatory elements directing pituitary-specific expression. DNA Cell Biol 1996; 15:679-92. [PMID: 8769570 DOI: 10.1089/dna.1996.15.679] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
To study the elements involved in the pituitary specific transcriptional regulation of the tilapia prolactin I gene (tiPRL I), we have cloned and entirely sequenced a 3.4-kb genomic fragment immediately upstream from the first exon. In footprinting experiments, three tilapia sequences are protected from DNase I digestion by rat pituitary extracts (base pair coordinates -643 to -593, -160 to -111, and -73 to -46). Computer analysis of the nucleotide sequence reveals significant homology to mammalian binding sites for Pit-1, a transcription factor that is known to mediate pituitary-specific expression of the PRL genes in mammals. The tiPRL I 5'-flanking sequences can direct transient expression of a linked luciferase reporter gene in transfected rat pituitary cell lines and tilapia pituitary primary cell cultures. Transient expression experiments with 5'-deletion mutants reveal three regulatory regions. Two have a stimulatory effect on transcription and one an inhibitory effect. Electrophoretic mobility-shift assays (EMSA) demonstrate that the rat Pit-1 factor specifically binds to tilapia DNA sequences. Several such tilapia Pit-1 binding sites mediate activation of a linked heterologous promoter in transfected rat and tilapia pituitary cells. As evidenced by EMSA, a Pit-1-like protein is present in tilapia pituitary extracts. All these data point to a high conservation of the molecular mechanisms involved in pituitary-specific expression of the PRL genes in vertebrates.
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Affiliation(s)
- A C Poncelet
- Laboratoire de Biologie Moléculaire et de Génie Génétique, Université de Liége, Sart-Tilman, Belgium
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Chen TT, Marsh A, Shamblott M, Chan KM, Tang YL, Cheng CM, Yang BY. 6 Structure and Evolution of Fish Growth Hormone and Insulinlike Growth Factor Genes. ACTA ACUST UNITED AC 1994. [DOI: 10.1016/s1546-5098(08)60067-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/16/2023]
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