Project description:A great number of studies have investigated changes induced by morphine exposure in gene expression using several experimental models. In this study, we examined gene expression changes during chronic exposure to morphine during maturation and differentiation of zebrafish CNS. Our study identified different functional classes of genes and individual candidates involved in the mechanisms underlying susceptibility to morphine actions related to CNS development. These results open new lines to study the treatment of pain and the molecular mechanisms involved in addiction. We also found a set of zebrafish-specific morphine-induced genes, which may be putative targets in human models for addiction and pain processes. Zebrafish embryos were divided into two experimental groups: control embryos and embryos at 5 hpf exposed to 10 nM morphine and collected at 24 hpf (covering the complete embryogenesis). Morphine was administered to the embryos in their water environment, i.e., diluted in E3 embryonic medium. The exposition to begun at the stage of 5 hpf (end of blastula) is continuous, in order to study the chronic effects of the exposure to drug. Microarray experiments were performed using six replicates for each condition, which contained the RNA of approximately one hundred embryos to minimize the influence of potential individual differences between the animals and technical variation introduced by tissue preparation. We previously reported that a concentration of 10 nM morphine is the highest concentration that can be used without a toxic effect on the embryos, and close to 5% of the morphine diluted in the E3 medium is detected in the embryo.
Project description:Methylmercury (MeHg) is an environmental neurotoxicant known to cause adverse effects in fish, such as locomotor abnormalities, visual deficits or teratogenesis. However, very few studies have investigated the effects of environmentally realistic MeHg exposures on the gene expression of fish embryos. Since the primary source of MeHg exposure in wild fish is through the diet, this study analyzed differential gene expression in zebrafish embryos from parents that had been subjected to environmentally relevant dietary MeHg exposures (0, 1, 3, and 10ppm) throughout their whole life cycle.
Project description:The exon junction complex (EJC) is composed of three core proteins Rbm8a, Magoh and Eif4a3 and is thought to play a role in several post-transcriptional processes. In this study we focus on understanding the role of EJC in zebrafish development. We identified transcriptome-wide binding sites of EJC in zebrafish via RNA:protein immunoprecipitation followed by deep sequencing (RIP-Seq). We find that, as in human cells, zebrafish EJC is deposited about 24 nts upstream of exon-exon junctions. We also identify transcripts regulated by Rbm8a and Magoh in zebrafish embryos using whole embryo RNA-seq from rbm8a mutant, magoh mutant and wild-type sibling embryos. This study shows that nonsense mediated mRNA decay is dysregulated in zebrafish EJC mutants.