Arsenite exposure disturbs maternal-to-zygote transition by attenuating H3K27ac during mouse preimplantation development [ChIP-seq]

Arsenite is mainly used as insecticides, antiseptic and herbicides. It enters the food chain through soil contamination, and then impedes human health, including of reproductive systems. Early embryos, as the initial stage of mammalian life, are very sensitive to the environmental toxins and pollutants. However, whether and how arsenite disturbs the early embryo development remains unknown. Here, we used mouse early embryo as a model and found that arsenite exposure did not induce reactive oxygen species production, DNA damage and apoptosis in early mouse embryos. However, arsenite exposure made embryonic development arrest at the 2-cell stage by altering their gene expression patterns. The transcriptional profile in the arrested embryos showed abnormal maternal-to-zygote transition (MZT). More importantly, arsenite exposure attenuated H3K27ac modification enrichment at the promoter region of Brg1 (a key gene for MZT), which inhibited its transcription, and further affected MZT and early embryonic development. Taken together, these results suggest that arsenite exposure affects MZT by reducing the enrichment of H3K27ac on the embryonic genome, and ultimately induces early embryonic development arrest at the 2-cell stage.