Project description:Migrasomes are recently identified vesicular organelles that form on retraction fibers behind migrating cells, cellular contents are released from migrasome by a process named migracytosis. The function of migrasomes in living organisms is unknown. Here we show that migrasomes are formed during zebrafish gastrulation, signaling molecules such as chemokines are enriched in migrasomes. Migrasomes are clustered on spatially restricted area in embryo where they provide regional cues for organ morphogenesis. Our study shown migrasome is signaling organelles which integrate spatial and specific biochemical information to coordinate migrating cells in complex biological processes such as morphogenesis.
Project description:Epigenetic regulation of chromatin states is crucial for proper gene expression programs and progression during development, but precise mechanisms by which epigenetic factors influence differentiation remain poorly understood. Here we find that the histone variant H2A.Z accumulates at Sox motif-containing promoters during zebrafish gastrulation while neighboring genes become transcriptionally active. These changes coincide with reduced expression of anp32e, the H2A.Z histone removal chaperone, suggesting that loss of Anp32e may lead to increases in H2A.Z binding during differentiation. Remarkably, genetic removal of Anp32e in embryos leads to H2A.Z accumulation prior to gastrulation and developmental genes become precociously active. Accordingly, H2A.Z accumulation occurs most extensively at Sox motif-associated genes, including many which are normally activated following gastrulation. Altogether, our results provide compelling evidence for a mechanism in which Anp32e preferentially restricts H2A.Z accumulation at Sox motifs to regulate the initial phases of developmental differentiation in zebrafish.
Project description:Cardiac development arises from two sources of mesoderm progenitors, the first (FHF) and the second heart field (SHF). Mesp1 has been proposed to mark the most primitive multipotent cardiac progenitors common for both heart fields. Here, using clonal analysis of the earliest prospective cardiovascular progenitors in a temporally controlled manner during the early gastrulation, we found that Mesp1 progenitors consist of two temporally distinct pools of progenitors restricted to either the FHF or the SHF. FHF progenitors were unipotent, while SHF progenitors, were either uni- or bipotent. Microarray and single cell RT-PCR analysis of Mesp1 progenitors revealed the existence of molecularly distinct populations of Mesp1 progenitors, consistent with their lineage and regional contribution. Altogether, these results provide evidence that heart development arises from distinct populations of unipotent and bipotent cardiac progenitors that independently express Mesp1 at different time points during their specification, revealing that the regional segregation and lineage restriction of cardiac progenitors occurs very early during gastrulation. We used microarrays to characterize the molecular mechanisms that control Mesp1 progenitor specification and lineage segregation during the early stage of cardiac mesoderm formation, 50 Mesp1 H2B-GFP+ or Mesp1 H2B-GFP- cells at E6.5 or E7.5 from mouse embryos were sorted for RNA extraction, amplification and hybridization on Affimetrix microarrays. Microaarrays were performed on Mouse Genome 430 PM strip Affymetrix array. The overall design was repeated in two different biological samples.
Project description:Gastrulation in the early post-implantation stage mammalian embryo begins when epiblast cells ingress to form the primitive streak or develop as the embryonic ectoderm. The DNA dioxygenase Tet1 is highly expressed in the epiblast and yet continues to regulate lineage specification during gastrulation when its expression is diminished. Here, we show how Tet1 plays a pivotal role upstream of germ layer lineage bifurcation. During the transition from naive pluripotency to lineage priming, a global reconfiguration re-distributes Tet1 from Oct4 co-bound promoters to distal regulatory elements at lineage differentiation genes which are distinct from high-affinity sites engaged by Oct4. An altered chromatin landscape in Tet1-deficient primed epiblast-like cells is associated with enhanced Oct4 expression and binding to Nodal and Wnt target genes, resulting in collaborative signals that enhance mesendodermal and inhibit neuroectodermal gene expression during lineage segregation. A permissive role for Tet1 in neural fate induction involves Zic2-dependent engagement at neural target genes at lineage priming, is dependent on the signaling environment during gastrulation and impacts neural tube closure at post-gastrulation. Our findings provide mechanistic information for epigenetic integration of pluripotency and signal-induced differentiation cues.
Project description:Gastrulation in the early post-implantation stage mammalian embryo begins when epiblast cells ingress to form the primitive streak or develop as the embryonic ectoderm. The DNA dioxygenase Tet1 is highly expressed in the epiblast and yet continues to regulate lineage specification during gastrulation when its expression is diminished. Here, we show how Tet1 plays a pivotal role upstream of germ layer lineage bifurcation. During the transition from naive pluripotency to lineage priming, a global reconfiguration re-distributes Tet1 from Oct4 co-bound promoters to distal regulatory elements at lineage differentiation genes which are distinct from high-affinity sites engaged by Oct4. An altered chromatin landscape in Tet1-deficient primed epiblast-like cells is associated with enhanced Oct4 expression and binding to Nodal and Wnt target genes, resulting in collaborative signals that enhance mesendodermal and inhibit neuroectodermal gene expression during lineage segregation. A permissive role for Tet1 in neural fate induction involves Zic2-dependent engagement at neural target genes at lineage priming, is dependent on the signaling environment during gastrulation and impacts neural tube closure at post-gastrulation. Our findings provide mechanistic information for epigenetic integration of pluripotency and signal-induced differentiation cues.
Project description:Here we describe successful implementation of CUT&RUN for profiling protein-DNA interactions in zebrafish embryos. We apply modified a CUT&RUN method to generate high resolution maps of enrichment for H3K4me3, H3K27me3, H3K9me3, and RNA polymerase II during zebrafish gastrulation. Using this data, we identify a conserved subset of developmental genes that are enriched in both H3K4me3 and H3K27me3 during gastrulation, and we demonstrate the increased effectiveness of CUT&RUN for detecting protein enrichment at repetitive sequences with reduced mappability. Our work demonstrates the power of combining CUT&RUN with the strengths of the zebrafish system to better understand the changing embryonic chromatin landscape and its roles in shaping development.
Project description:Cardiac development arises from two sources of mesoderm progenitors, the first (FHF) and the second heart field (SHF). Mesp1 has been proposed to mark the most primitive multipotent cardiac progenitors common for both heart fields. Here, using clonal analysis of the earliest prospective cardiovascular progenitors in a temporally controlled manner during the early gastrulation, we found that Mesp1 progenitors consist of two temporally distinct pools of progenitors restricted to either the FHF or the SHF. FHF progenitors were unipotent, while SHF progenitors, were either uni- or bipotent. Microarray and single cell RT-PCR analysis of Mesp1 progenitors revealed the existence of molecularly distinct populations of Mesp1 progenitors, consistent with their lineage and regional contribution. Altogether, these results provide evidence that heart development arises from distinct populations of unipotent and bipotent cardiac progenitors that independently express Mesp1 at different time points during their specification, revealing that the regional segregation and lineage restriction of cardiac progenitors occurs very early during gastrulation. We used microarrays to characterize the molecular mechanisms that control Mesp1 progenitor specification and lineage segregation during the early stage of cardiac mesoderm formation,
Project description:We investigated salinity adaptation during the migration from freshwater to seawater of European eel (Anguilla anguilla) by examining the hypothesis that: The brain is the central organ for the co-ordination of environmental cues (day length, photoperiod, temperature and environmental salinity) with the anatomical and physiological adaptations which accompany pre-migrational morphogenesis and the osmoregulatory plasticity seen in post-migrational, salinity-adapted fish. We have characertised the mRNA expression profiles for the brains of fresh water and sea water adapted silver eel using a highly representative brain cDNA microarray. The array comprises 5760 cDNA clones from A.anguilla ranging from 0.5 -10 kb and an estimated redundancy of > 5 %.
Project description:Study of hypoxia-induced differential expression during zebrafish development at gastrulation (shield) and segmentation (8-somite) stages
Project description:Coordinated cell movements of gastrulation reshape the uniform blastula into a structured gastrula with three fundamental axes and an internal germ layer of mesoderm. Genetic regulation of the forces which drive gastrulation is incompletely understood. We employed a microarray screen in zebrafish for genes which are dynamically expressed during embryonic development. In particular, we were interested in exploring genes that are expressed during the gastrulation.