@article{SchartlKneitzVolkoffetal.2019, author = {Schartl, Manfred and Kneitz, Susanne and Volkoff, Helene and Adolfi, Mateus and Schmidt, Cornelia and Fischer, Petra and Minx, Patrick and Tomlinson, Chad and Meyer, Axel and Warren, Wesley C.}, title = {The piranha genome provides molecular insight associated to its unique feeding behavior}, series = {Genome Biology and Evolution}, volume = {11}, journal = {Genome Biology and Evolution}, number = {8}, doi = {10.1093/gbe/evz139}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-202218}, pages = {2099-2106}, year = {2019}, abstract = {The piranha enjoys notoriety due to its infamous predatory behavior but much is still not understood about its evolutionary origins and the underlying molecular mechanisms for its unusual feeding biology. We sequenced and assembled the red-bellied piranha (Pygocentrus nattereri) genome to aid future phenotypic and genetic investigations. The assembled draft genome is similar to other related fishes in repeat composition and gene count. Our evaluation of genes under positive selection suggests candidates for adaptations of piranhas' feeding behavior in neural functions, behavior, and regulation of energy metabolism. In the fasted brain, we find genes differentially expressed that are involved in lipid metabolism and appetite regulation as well as genes that may control the aggression/boldness behavior of hungry piranhas. Our first analysis of the piranha genome offers new insight and resources for the study of piranha biology and for feeding motivation and starvation in other organisms.}, language = {en} } @article{SchartlSchoriesWatamatsuetal.2018, author = {Schartl, Manfred and Schories, Susanne and Watamatsu, Yuko and Nagao, Yusuke and Hashimoto, Hisashi and Bertin, Chlo{\´e} and Mourot, Brigitte and Schmidt, Cornelia and Wilhelm, Dagmar and Centanin, Lazaro and Guiguen, Yann and Herpin, Amaury}, title = {Sox5 is involved in germ-cell regulation and sex determination in medaka following co-option of nested transposable elements}, series = {BMC Biology}, volume = {16}, journal = {BMC Biology}, number = {16}, doi = {10.1186/s12915-018-0485-8}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-175827}, year = {2018}, abstract = {Background: Sex determination relies on a hierarchically structured network of genes, and is one of the most plastic processes in evolution. The evolution of sex-determining genes within a network, by neo- or sub-functionalization, also requires the regulatory landscape to be rewired to accommodate these novel gene functions. We previously showed that in medaka fish, the regulatory landscape of the master male-determining gene dmrt1bY underwent a profound rearrangement, concomitantly with acquiring a dominant position within the sex-determining network. This rewiring was brought about by the exaptation of a transposable element (TE) called Izanagi, which is co-opted to act as a silencer to turn off the dmrt1bY gene after it performed its function in sex determination. Results: We now show that a second TE, Rex1, has been incorporated into Izanagi. The insertion of Rex1 brought in a preformed regulatory element for the transcription factor Sox5, which here functions in establishing the temporal and cell-type-specific expression pattern of dmrt1bY. Mutant analysis demonstrates the importance of Sox5 in the gonadal development of medaka, and possibly in mice, in a dmrt1bY-independent manner. Moreover, Sox5 medaka mutants have complete female-to-male sex reversal. Conclusions: Our work reveals an unexpected complexity in TE-mediated transcriptional rewiring, with the exaptation of a second TE into a network already rewired by a TE. We also show a dual role for Sox5 during sex determination: first, as an evolutionarily conserved regulator of germ-cell number in medaka, and second, by de novo regulation of dmrt1 transcriptional activity during primary sex determination due to exaptation of the Rex1 transposable element.}, language = {en} } @article{HerpinAdolfiNicoletal.2013, author = {Herpin, Amaury and Adolfi, Mateus C. and Nicol, Barbara and Hinzmann, Maria and Schmidt, Cornelia and Klughammer, Johanna and Engel, Mareen and Tanaka, Minoru and Guiguen, Yann and Schartl, Manfred}, title = {Divergent Expression Regulation of Gonad Development Genes in Medaka Shows Incomplete Conservation of the Downstream Regulatory Network of Vertebrate Sex Determination}, series = {Molecular Biology and Evolution}, volume = {30}, journal = {Molecular Biology and Evolution}, number = {10}, doi = {10.1093/molbev/mst130}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-132262}, pages = {2328-2346}, year = {2013}, abstract = {Genetic control of male or female gonad development displays between different groups of organisms a remarkable diversity of "master sex-determining genes" at the top of the genetic hierarchies, whereas downstream components surprisingly appear to be evolutionarily more conserved. Without much further studies, conservation of sequence has been equalized to conservation of function. We have used the medaka fish to investigate the generality of this paradigm. In medaka, the master male sex-determining gene is dmrt1bY, a highly conserved downstream regulator of sex determination in vertebrates. To understand its function in orchestrating the complex gene regulatory network, we have identified targets genes and regulated pathways of Dmrt1bY. Monitoring gene expression and interactions by transgenic fluorescent reporter fish lines, in vivo tissue-chromatin immunoprecipitation and in vitro gene regulation assays revealed concordance but also major discrepancies between mammals and medaka, notably amongst spatial, temporal expression patterns and regulations of the canonical Hedgehog and R-spondin/Wnt/Follistatin signaling pathways. Examination of Foxl2 protein distribution in the medaka ovary defined a new subpopulation of theca cells, where ovarian-type aromatase transcriptional regulation appears to be independent of Foxl2. In summary, these data show that the regulation of the downstream regulatory network of sex determination is less conserved than previously thought.}, language = {en} } @article{MenescalSchmidtLiedtkeetal.2012, author = {Menescal, Luciana and Schmidt, Cornelia and Liedtke, Daniel and Schartl, Manfred}, title = {Liver hyperplasia after tamoxifen induction of Myc in a transgenic medaka model}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-75316}, year = {2012}, abstract = {Myc is a global transcriptional regulator and one of the most frequently overexpressed oncoproteins in human tumors. It is well established that activation of Myc leads to enhanced cell proliferation but can also lead to increased apoptosis. The use of animal models expressing deregulated levels of Myc has helped to both elucidate its function in normal cells and give insight into how Myc initiates and maintains tumorigenesis. Analyses of the medaka (Oryzias latipes) genome uncovered the unexpected presence of two Myc gene copies in this teleost species. Comparison of these Myc versions to other vertebrate species revealed that one gene, myc17, differs by the loss of some conserved regulatory protein motifs present in all other known Myc genes. To investigate how such differences might affect the basic biological functions of Myc, we generated a tamoxifeninducible in vivo model utilizing a natural, fish-specific Myc gene. Using this model we show that, when activated, Myc17 leads to increased proliferation and to apoptosis in a dose-dependent manner, similar to human Myc. We have also shown that long-term Myc17 activation triggers liver hyperplasia in adult fish, allowing this newly established transgenic medaka model to be used to study the transition from hyperplasia to liver cancer and to identify Myc-induced tumorigenesis modifiers.}, subject = {Biologie}, language = {en} }