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.
Project description:Cypermethrin (CYP) and chlorpyrifos (CPF) are pesticides which are frequently used in agricultural areas around the world. These chemicals have been shown to cause serious toxicological damage in the brain of fish, which is non-target organisms. However, circRNAs associated with acute brain toxicity caused by cypermethrin and chlorpyrifos have not been studied yet. In this study, circRNAs were identified and characterized using RNA-seq in Zebrafish brains exposed to acute cypermethrin and chlorpyrifos toxicity. A total of 10375 circRNAs were detected. It was determined that 6 circRNAs were up-regulated, 10 circRNAs were down-regulated in CYP brain samples compared to controls . In addition, it was found that 57 circRNAs are up-regulated and 3 circRNAs down-regulated in CPF brain samples compared to controls. Moreover, 62 circRNAs were down-regulated in the CYP samples, when CYP and CPF samples were compared. However, up-regulated circRNA could not be detected. It was revealed that the detected circRNAs specifically regulated the MAPK signaling pathway, endocytosis mechanism, apoptosis and p53 signaling pathway. This study, which was conducted for the first time in terms of the subject of the study, could bring a different perspective especially to pesticide toxicity studies.
Project description:We used microarray analyses in adult female zebrafish (Danio rerio) to identify metabolic pathways regulated by starvation in two key organs that 1) serve biosynthetic and energy mobilizing functions (liver) and 2) consume energy and direct behavioral responses (brain). Starvation affected the expression of 574 transcripts in the liver, indicating an overall decrease in metabolic activity, reduced lipid metabolism, protein biosynthesis and proteolysis, and cellular respiration, and increased gluconeogenesis. Starvation also regulated expression of many components of the Unfolded Protein Response, the first such report in a species other than yeast (Saccharomyces cerevisiae) and mice (Mus musculus). The response of the zebrafish hepatic transcriptome to starvation was strikingly similar to that of rainbow trout (Oncorhynchus mykiss), but very different from common carp (Cyprinus carpio) and mouse. The transcriptome of zebrafish whole brain was much less affected than the liver, with only two differentially expressed genes, both down-regulated. Down-regulation of one of these genes, matrix metalloproteinase 9 (mmp9), suggests increased inhibition of apoptosis (neuroprotection) and decreased restructuring of the extracellular matrix in the brain of starved zebrafish. The low level of response in the transcriptome of whole zebrafish brain agrees with observations that the brain is metabolically protected compared to the rest of the body. Keywords: starvation study