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Browsing by Author "Martins, Rute S.T."

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  • Somatostatin 4 regulates growth and modulates gametogenesis in zebrafish
    Publication . Sui, Chenchao; Chen, Jie; Ma, Jing; Zhao, Wenting; Canario, Adelino V.M.; Martins, Rute S.T.
    Somatostatin (SST) plays important roles in growth and development. In teleost fishes six SST encoding genes (sst1 to sst6) have been identified although few studies have addressed their function. Here we aim to determine the function of the teleost specific sst4 in the zebrafish. A CRISPR/Cas9 sst4 zebrafish mutant with loss of function (sst4−/−) was produced which grew significantly faster and was heavier at the onset of gonadal maturation than the wild type (WT). Consistent with their faster growth, liver igf1, igf2a and igf2b expression was significantly upregulated in the sst4−/− fish compared to the WT. Histological examination of the ovaries and testis indicated that sst4−/− fish had slightly delayed testicular gametogenesis compared to the WT. Significantly lower expression of igf3, amh, insl3, hsd17b3, hsd11b2, hsd20b, cyp11b and cyp17 was consistently observed in the sst4−/− testis. In contrast, the ovaries had lower expression of igf1, igf2a and cyp19a1a but increased expression of igf2b and hsd20b. The gonadotrophin beta subunits (fshb and lhb) in the brain were downregulated indicating the brain-pituitary-gonadal axis was downregulated in the sst4−/− fish and suggesting that the steroid production is compromised in the maturing gonads. In addition, analysis of sst1 and sst3 mRNA levels in sst4−/− fish suggests a dosage compensation effect of sst1 in the brain and liver. Altogether, the results from the zebrafish sst4−/− line support the idea that sst4 is involved in the regulation of igf signalling, somatic growth and reproduction since steroidogenesis and gametogenesis at pubertal onset were compromised.
    2019Journal article Open access Show more
  • SuperSAGE digital expression analysis of differential growth rate in a European sea bass population
    Publication . Louro, Bruno; Martins, Rute S.T.; Pinto, Patricia IS; Reinhardt, Richard; de Koning, Dirk-Jan; Canario, Adelino; Power, Deborah
    One of the goals of the aquaculture industry is to understand and control growth associated traits through selective breeding. In the present study the molecular basis of growth heterogeneity in the European sea bass (Dicentrarchus labrax) was addressed. To establish growth heterogeneity in a group of hatchery bred sea bass individuals were tagged and their specific growth rates (SGR) determined at monthly intervals. Gene expression in the brain, liver and white muscle from fish with the most divergent sustained SGR (6 individuals of the first and last quartile) was assessed using SuperSAGE (Serial Analysis Gene Expression) combined with next generation SOLiD4 sequencing. A total of approx. 11 million edited tags (26 bp), on average 2 million tags per SAGE library, that represented 47.071 unique transcripts were identified. Comparison of transcripts in fish with high and low SGR yielded 344, 698 and 601 differently expressed tags (0.01% false discovery rate and 4-fold change) in brain, liver and muscle, respectively. The tags were mapped onto the sea bass genome and approximately one third of the tags could be assigned to annotated genes. Pathway enrichment analysis revealed in liver, muscle and brain intricate gene expression changes in endocrine regulatory pathways involved in growth, metabolic and the stress axis, underlying divergent SGR in sea bass.
    2019Journal article Open access Show more