43 research outputs found
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Presentation of Dogmatis, An Inter and Multidisciplinary Programme for the Assessment of the Impacts of Genetically Modified Fish, and Results About Risk of fortuitous Import on French Market
DOGMATIS is a research project funded by the French Research Agency (ANR, programme ANR-OGM 2007-2010). The transgenic technologies have been applied to fish since more than 20 years now and some strains are at the premarket or market stage in countries outside Europe. In Europe the main risk is a fortuitous import. Any rumour of uncontrolled arrival of GM fish on the European market may have strong impacts on the market chain, the research and innovation system and the trust in public regulation. The aim of DOGMATIS is to anticipate the answers. It associates specialists of fish transgenesis, GMO detection and regulation, fish market chain economy, consumer sociology and contemporary science philosophy and epistemology. To tackle this multifactorial subject, we developed original methodologies including assumptions based on the quantitative and qualitative knowledge from the different experts of DOGMATIS. We propose to present the programme and the results of our investigation concerning an assessments of the risk of fortuitous presence of GM Fish on the French market, which has been done by crossing the data from scientific literature gathered in a data bank and an expert analysis of filtered statistics of international trade, for the two farmed species concerned by transgenesis techniques and imported on the French market, salmon and tilapia.Keywords: Posters, Markets and Trade, Fisheries Economic
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Copy Number Related Transgene Expression and Mosaic Somatic Expression in Hemizygous and Homozygous Transgenic Tilapia (Oreochromis Niloticus)
Three lines of transgenic tilapia (Oreochromisniloticus) fish were generated with a constructcontaining a lacZ reporter gene spliced to a 4.7 kb 5′ regulatory region of a carp beta actin gene. All these three lines contain different copy numbers oftransgenes and the levels of lacZ expressionwere found to be related to transgene copy number. Mosaic patterns of somatic lacZ expression were observed in these three lines which differed between lines but were consistent within a line. We also observedthat expression of the reporter gene in homozygoustransgenic fish was approximately two-fold greater than in the hemizygous transgenics. Analysis of expressionof the reporter gene on a tissue-to-tissue basisdemonstrated that lacZ expression of thereporter gene in stably transformed fish occured withvariable intensity in different organs and tissues andwas also sometimes variable in different cells of thesame tissue in G1and G2 generations of the transgenic line
Developmental expression and estrogenic regulation of Kiss2 using a transgenic zftg(kiss2-GFP) zebrafish line
The recent discoveries of the kisspeptin system and its involvement in reproduction have been major breakthroughs in neuroendocrinology. In zebrafish, two kisspeptins (Kiss1 and Kiss2) and two kisspeptins receptors (GPR54.1 = Kiss1r and GPR54.2 = Kiss2r) are expressed and each of them is encoded by a single gene. Recently, we have fully described the distribution of the kisspeptins and their receptors in the brain of adult zebrafish. Kiss2 expressing neurons are mostly localized in the dorsal and ventral hypothalamus. They project widely in the midbrain and anterior brain in regions expressing the Kiss2r and are likely in contact with GnRH3 fibers. In contrast, Kiss1 expressing neurons are exclusively localized in the habenula, which also expresses the Kiss1r, and project in the interpeduncular and raphe nuclei. These results suggest a gene speciation in zebrafish, with the Kiss2 system involved in reproductive processes and the Kiss1 system in interactions with others processes like food intake or environmental perception. Interestingly, exposure of juvenile zebrafish to estrogens up-regulates the kiss2 gene, suggesting that the Kiss2 system could mediate the neuroendocrine control of reproduction by estrogens. In order to study (i) the kiss2 expression in early development and (ii) the modulation of this expression in response to estrogens, we developed a transgenic zebrafish line, zftg(kiss2-GFP), expressing GFP under the control of the zebrafish kiss2 promoter. This zebrafish transgenic line, validated by immunohistochemistry, expresses GFP as early as 4 dpf in the hypothalamus, demonstrating that the kiss2 system is functional widely before sexual maturation. Moreover, exposure of zebrafish embryos to estrogens enhances the number of Kiss2 immunoreactive-fibers, suggesting that estrogens modulate the development of kiss2 neurons. Taken together, these results reinforce the view that, in zebrafish, kiss2 is probably linked to the regulation of reproductive processes. Moreover, the zftg(kiss2-GFP) line appears to be a promising tool to study the role of Kiss2 in early development, notably its interaction with the GnRH system, but also its potential disruption by environmental estrogenic compounds
The Proximal Promoter Region of the Zebrafish gsdf Gene Is Sufficient to Mimic the Spatio-Temporal Expression Pattern of the Endogenous Gene in Sertoli and Granulosa Cells.
International audienceThe gonadal soma-derived factor (GSDF) is a new member of the transforming growth factor beta (TGFbeta) superfamily that regulates the proliferation of the primordial germ cells (PGC) in developing embryos and spermatogonia in juvenile male trout. The gsdf transcripts are expressed in the somatic cells supporting germ cell development. In zebrafish, we show that Gsdf is encoded by a single copy gene that generates polymorphic transcripts and proteins. We determined that gsdf gene expression occurs before gonadal differentiation and is restricted to the gonads. Gene expression is maintained in adult granulosa cells and Sertoli cells, but decreases in the cells that are in contact with meiotic and postmeiotic germ cells. Using zebrafish transgenic lines, we demonstrate that the 2 kb proximal promoter region of the gsdf gene targets high level of transgene expression in the Sertoli and granulosa cells, and is sufficient to mimic the temporal expression pattern of the endogenous gsdf gene from 16 dpf onwards. We identified within the first 500 bp, evolutionary conserved DNA motifs that may be involved in Sertoli and granulosa cell-specific expression. However, the 2kb proximal promoter region failed to drive efficient expression of the transgene in the gonads in four transgenic medaka lines. We propose that the proximal promoter region can be used to target candidate gene deregulation in zebrafish granulosa and Sertoli cells. Furthermore, the GFP expressing zebrafish lines produced in the present study are new valuable models for cell lineage tracing during sex differentiation and gametogenesis
Des poissons modèles fluorescents pour la caractérisation fonctionnelle de promoteurs géniques
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Activation of gene transcription by tilapia prolactin variants tiPRL188 and tiPRL177
5 graph.International audienceIn the tilapia species Oreochromis niloticus, the pituitary releases two forms of prolactins (tiPRL(188) and tiPRL(177)) The binding parameters and the activation of tiPRL-induced JAK2/Stat5 signalling pathway were analysed using a mammalian cell line transiently transfected with the tiPRL receptor (tiPRLR). Our data indicate that the tiPRLR is able to mediate transcriptional activation of the PRL responsive element, At nanomolar concentrations, tiPRL(188) activates gene transcription whereas at micromolar concentrations it inhibits luciferase transcription from the lactogenic responsive element. This is consistent with a model of receptor dimerisation, In contrast, the activation by tiPRL177 was only reached at high (mu M) concentrations. The transcriptional activities induced by tiPRL(177) and tiPRL(188) are discussed in the context of the physiology of these hormones
Des poissons modèles fluorescents pour la caractérisation fonctionnelle de promoteurs géniques
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GSDF is included in a cluster of genes evolutionary conserved and preferentially expressed in the gonads
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