Project description:Upon fertilization, the embryonic genome remains transcriptionally inactive until the mid-blastula transition. Zygotic genome activation (ZGA) of vertebrate embryos has been extensively studied using nucleic acid-based strategies, but proteomics data are still scarce, impeding the full mechanistic understanding of how ZGA is executed during the maternal-to-zygotic transition (MZT). Here, we performed quantitative proteomics to decipher the proteome landscape of zebrafish embryos during the MZT, quantifying nearly 5,000 proteins across four embryonic stages. The stage-specific clustering based on protein expression pattern revealed that helicases (i.e., eif4a2 and ruvbl1) facilitate pluripotency factors (i.e., nanog, pou5f3, ctcf, and hmga1) triggering ZGA in zebrafish, accompanied by the maternal product decay with P-bodies and ubiquitin dependent proteolytic pathway. Dozens of transcription factors show wave-like expression patterns during MZT, implying their diverse functions in triggering the ZGA and modulating differentiation for organ development. The combination of morpholino knockdown and quantitative proteomics demonstrated that maternal Nanog is required for proper embryogenesis by regulating 1) interactions with other pluripotency factors, 2) F-actin band formation, 3) cell cycle checkpoints and 4) maternal product degradation. This study represents the most systematic proteomics survey of developmentally regulated proteins and their expression profiles accompanying MZT in zebrafish, which is a valuable proteome resource for understanding ZGA.
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:Zebrafish (Danio rerio) model system have used widespread vertebrate investigations for genetic and cell biological analyses, and is suitable for small molecular screens such as chemical, toxicity and drug in order to use for human diseases and drug discovery . Recently, These powerful zebrafish model increasingly apply to human metabolic disease such as obesity and diabetes and toxicology. Despite a lot of advantages, proteomics research at zebrafish has received little interest in comparison with genetic and biological research using histology and in situ hybridization. Protein lysine acetylation is one of the most known post-translational modifications with dynamic and reversibly controlled by lysine acetyltransferase such as histone acetyltransferases and lysine deacetylase such as histone deacetylases and sirtuins family.Also, during the past year, global lysine acetylome studies using MS-based proteomics approach was in diverse species such as human, mouse, E. coli, Yeast and plants. Based on global acetylome data, our understanding of the roles of lysine acetylation in various cellular processes has increased. . The aim of this study was to identify Lysine acetylation in zebrafish embryos and determine the homology from Human at modified site level. Here we showed the global lysine acetylation study in Zebrafish embryos using MS-based zebrafish embryos.
Project description:In this study, we interrogated the role of DNA methylation in HSPC generation by taking advantage of dnmt1 knockout/knockdown embryos in zebrafish. First, we generated a comprehensive DNA methylation landscape of EHT, which revealed gradually hypermethylated regions associated with vasculogenesis. Taking advantage of dnmt1-deficient embryos, we showed that the decreased DNA methylation blocked HSPC emergence. Mechanistically, we demonstrated that the decreased DNA methylation increased the expression of arterial genes and Notch signaling, thus contributing to defects in the EHT in dnmt1-deficient embryos. Herein, we identified that DNA methylation, as epigenetic regulator, participates in the negative modulation of Notch signaling through inhibiting transcription during HSPC generation in zebrafish.