Project description:In zebrafish embryos, the maternal transcription factors (TFs)Nanog, Pou5f3 and Sox19b activate the early zygotic gene expression. To evaluate the role of Nanog, we examined the changes in H3K27ac and H3K4me3 chromatin modifications in the MZnanog embryos mutant by maternal and zygotic Nanog.
Project description:Genetic control of pluripotent mammalian ES cells is determined by a transcriptional network, with a "central core" of transcription factors, Pou5f1, Sox2 and Nanog. Zebrafish homologues of the "core pluripotency factors" Pou5f1, SoxB1 and Nanog-like are also crucially involved in early development. However, the degree of functional similarity of the network between mammals and non-mammals is a matter of debate. To identify the components of Pou5f1-dependent transcriptional networks, we determined the genomic binding sites for Pou5f1 and Sox2 in late blastula stage zebrafish embryos using ChIP-seq. We found that Sox2 and Pou5f1 are co-binding to the regulatory regions of Sox2, Pou5f1, and Nanog-like, as well as to multiple orthologues of mammalian plutipotency network components. Deep sequencing was performed using the Illumina GAIIx on DNA samples obtained from Sox2 ChIP, Pou5f1-Flag ChIP and Input Control. Pou5f1 was analysed in technical duplicates to obtain higher sequencing depth.
Project description:This SuperSeries is composed of the following subset Series: GSE34682: Expression analysis of Nanog-like-MO1 injected zebrafish embryos at the sphere stage GSE34683: Genome-wide maps of binding sites of Nanog-like and Mxtx2 in blastula stage zebrafish embryos Refer to individual Series
Project description:Here, using ChIP-Seq, we examined the targets of Nanog-like and Mxtx2 in blastula stage zebrafish embryos. We found that Nanog-like bind to its known targets like Oct4, Sox2, and Nanog-like. Nanog-like also bound to genes involved in extraembryonic lineage differentiation, like gata3 and krt4 for EVL differentiation, and mxtx2 and slc26a1 for YSL differentiation, mesoderm specification like ntl and tbx3, cell movement like wnt11 and cxcr4b, and signaling genes like ndr1, bmp2b, fgf8a and wnt8a. The binding profile suggests that Nanog-like may play a versatile role involving many developmental processes. We found 11.3% of the genes (1751 out of all annotated 15500 zebrafish genes) and 43.6% of the YSL genes (118 out of 271 genes expressed in the YSL) were bound by Mxtx2, suggesting Mxtx2 bound directly to YSL genes to activate their expression Examination of Nanog-like and Mxtx2 binding sites in 3.5hpf and 4.5hpf zebrafish embryos
Project description:Nanog null neural stem (NS) cells were reprogrammed to naive pluripotency in 2i/LIF conditions with chick (c) and zebrafish (z) Nanog orthologs. Global gene expression was compared to iPS cells derived with mouse (m) Nanog. Murine iPS cells derived with zebrafish nanog, chick nanog, and mouse nanog orthologs (2 replicates each).
Project description:Purpose: Find out the consequences of Pou5f3/Oct4 and Nanog binding to the nucleosome distribution before and after Zygotic Genome Activation Methods: MNase-seq of the wild-type(WT), Pou5f3 (MZspg) and Nanog (MZnanog) mutant zebrafish embryos at 512-cell stage and dome stage. Results: Nanog, Sox19b and Pou5f3 bind to the High Nucleosome Affinity Regions (HNARs). HNARs are spanning over 600 bp, featuring high in vivo and predicted in vitro nucleosome occupancy and high predicted propeller twist DNA shape value. We suggest a two-step model, where the same intrinsic DNA properties of HNAR promote both high nucleosome occupancy and differential binding of TFs. In the first step, already prior to ZGA, Pou5f3 and Nanog reduce nucleosome occupancy on HNARs genome-wide. In the second step, Nanog and Pou5f3/SoxB1 complex maintain open chromatin state on the subset of HNARs, acting synergistically. Nanog binds to the HNAR center, while the Pou5f3/SoxB1 complex stabilizes the flanks.
Project description:Upon fertilization, maternal factors direct development in a transcriptionally silent embryo. At the maternal-to-zygotic transition (MZT), a universal step in animal development, unknown maternal factors trigger zygotic genome activation (ZGA). In zebrafish, ZGA is required for gastrulation and clearance of maternal mRNAs, which is achieved in part by the conserved microRNA miR-430. However, the precise factors that activate the zygotic program remain largely unknown. Here we show that Nanog, Pou5f1 and SoxB1 are required for genome activation in zebrafish. We identified several hundred genes directly activated by maternal factors, thus constituting the first wave of zygotic transcription in zebrafish. Ribosome profiling in the pre-MZT embryo revealed that nanog, sox19b and pou5f1 are the most highly translated transcription factor mRNAs. Combined loss of function for Nanog, SoxB1 and Pou5f1 resulted in developmental arrest prior to gastrulation, and a failure to activate >75% of zygotic genes. Furthermore, we found that Nanog binds the miR-430 locus and together with Pou5f1 and SoxB1 initiate miR-430 expression and activity. Our results demonstrate that maternal Nanog, Pou5f1 and SoxB1 are required to initiate the zygotic developmental program and in turn trigger the clearance of the maternal program by activating miR-430 expression. Wild type and loss-of-function total mRNA sequencing of embryonic transcriptomes pre- and post-MZT; ribosome profiling pre-MZT
Project description:To understand the role of Pou5f3, Sox19b and Nanog during zebrafish zygotic genome activation, RNA-seq time-series for single, double and triple maternal-zygotic (MZ) zebrafish mutants for Pou5f3, Nanog, Sox19b, as well as the wild-type.
Project description:Here, using ChIP-Seq, we examined the targets of Nanog-like and Mxtx2 in blastula stage zebrafish embryos. We found that Nanog-like bind to its known targets like Oct4, Sox2, and Nanog-like. Nanog-like also bound to genes involved in extraembryonic lineage differentiation, like gata3 and krt4 for EVL differentiation, and mxtx2 and slc26a1 for YSL differentiation, mesoderm specification like ntl and tbx3, cell movement like wnt11 and cxcr4b, and signaling genes like ndr1, bmp2b, fgf8a and wnt8a. The binding profile suggests that Nanog-like may play a versatile role involving many developmental processes. We found 11.3% of the genes (1751 out of all annotated 15500 zebrafish genes) and 43.6% of the YSL genes (118 out of 271 genes expressed in the YSL) were bound by Mxtx2, suggesting Mxtx2 bound directly to YSL genes to activate their expression
Project description:Pioneer transcription factors Nanog, Pou5f3 and Sox19b promote chromatin accessibility on the enhancers of the early zebrafish embryos. It is poorly understood how they act together; it is commonly assumed that they act additively or cooperatively to clear chromatin from the nucleosomes. We investigated this question by comparing chromatin accessibility (Omni ATAC-seq) in seven mutant genotypes: single, double and triple maternal-zygotic mutants by Pou5f3, Sox19b and Nanog, and the wild-type embryos. We found, that at most of the directly bound sites, either Pou or Nanog is required for chromatin accessibility; while at the minority of the sites two factors act additively. Further, on the sites, where Pou5f3 promotes chromatin accessibility, Nanog often suppresses it, and vice versa. To explain this phenomenon, we suggest a model of nucleosome-mediated competition between pioneer transcription factors: Pou5f3 and Nanog compete for the same binding motif on the DNA, but only one of the factors has a pioneer activity on this site. This entry contains only part fo the Omni-ATAC-seq experiments, the other part is in the previously released entry GSE188364.