H3K4me3 and H3K27me3 modification profiling in early zebrafish embryo

Multicellular organism requires concise gene regulation during ontogeny and epigenetic modifications, such as DNA methylation and histone modification, facilitate the concise regulation. The conservative reprogramming patterns of DNA methylation in vertebrates have been well described but knowledge of how histone modifications are passed on to zygote from gametes are limited and conservations of histone modifications are not clear.We profiled H3K4me3/H3K27me3 modifications in gametes and early embryos in zebrafish and find out that patterns in gene promoter regions have been largely set to either bivalent or active states in gametes and then passed on to zygote. Bivalent states are partially maintained and active states are restored to match sperm’s pattern. But repressive H3K27me3 modifications as well as stage specific modifications in promoter regions are discarded. Prior to zygotic genome activation, patterns of genes that initialize ZGA have been converted to non-repressive states to coordinate gene expression. Histone modification in hyper methylated promoter peaks are erased independent of DNA methylome reprogramming. Comparative analysis revealed that functions of bivalent and active genes passed on from gametes are conserved in vertebrates and gene age preferences by bivalent and active histone modifications are also confirmed in vertebrates. H3K4me3 and H3K27me3 ChIP-seq with two replicates were performed for sperm/oocyte,2-cell, 16-cell, 128-cell and 1K-cell in zebrafish