Project description:We performed expression analysis of 7-10 zygotes after natural mating of superovulated JaxJ naive primiparous females and males that have undergone early life stress.
Project description:The epigenome plays critical roles in controlling gene expression and development. However, how the parental epigenomes transit to the zygotic epigenome in early development remains elusive. Here, we show parental-to-zygotic transition in zebrafish involves extensive erasure of parental epigenetic memory starting by methylating gametic enhancers. Surprisingly, this occurs even prior to fertilization for sperm. Both parental enhancers lose histone marks by the 4-cell stage, and zygotic enhancers are not activated until around zygotic genome activation (ZGA). By contrast, many promoters remain hypomethylated and, unexpectedly, acquire de novo histone acetylation as early as at the 4-cell stage. They then resolve into either activated or repressed promoters upon ZGA. Maternal depletion of histone acetyltransferases results in aberrant ZGA and early embryonic lethality. Finally, such reprogramming is largely driven by maternal factors with zygotic products contributing to embryonic enhancer activation. Thus, these data revealed widespread enhancer dememorization and promoter priming during parental-to-zygotic transition.
Project description:We performed expression analysis of 7-10 4-cell embryos resulting from sperm fragmented long RNA injections from control males or males exposed to early life stress into naive zygotes after female superovulation and natural mating with males.
Project description:Histone modifications regulate gene expression and development. To address how they are reprogrammed in human early development, we investigated key histone marks in human oocytes and early embryos. Unlike that in mouse, the permissive mark H3K4me3 largely exhibits canonical patterns at promoters in human oocytes. After fertilization, pre-zygotic genome activation (ZGA) embryos acquire permissive chromatin and widespread H3K4me3 in CpG-rich regulatory regions. By contrast, the repressive mark H3K27me3 undergoes global depletion. CpG-rich regulatory regions then resolve to either active or repressed states upon ZGA, followed by subsequent restoration of H3K27me3 at developmental genes. Finally, through combining chromatin and transcriptome maps, we revealed transcription circuitry and asymmetric H3K27me3 patterning during early lineage specification. Collectively, our data unveil a priming phase connecting human parental-to-zygotic epigenetic transition.
Project description:The R-loop is a common chromatin feature presented from prokaryotic to eukaryotic genomes and has been revealed to be involved in multiple cellular processes. Here, we developed a novel R-loop profiling technique, ULI-ssDRIP-seq, to decte global R-loops from a limited number of cells. Based on this method, we profiled the R-loop landscapes during parental-to-zygotic transition and early development regulatory in zebrafish, and revealed a series of important characters of R-loops.
Project description:In this study we hypothesize that early life stress perturbs the normal function of microglial in the developing hippocampus and that this effect is responsible for the ability of early life tress to disrupt normal synaptic maturation, myelination, and axonal growth in the developing hippocampus. To test this hypothesis we used the mouse immune panel from NanoString in order to identify immune-related genes whose expression is modified by BDS, a mouse model of early life stress, in microglia isolated from the hippocampus of 28-day old male pups. This project is part of a manuscript that is currently under preparation (Delpech J.C. et al. Early life stress perturbs the maturation of microglia in the developing hippocampus, Brain, Behavior and Immunity, 2016)