Epigenetic remodeling during early embryonic development

In mammals, the fusion of sperm and oocyte gives rise to a totipotent zygote, which undergoes a series of cleavage divisions and differentiation events. During this process, the embryo transitions from totipotency to pluripotency, accompanied by extensive epigenetic reprogramming. With continuous innovation of low-input multi-omics technology and other methods, the relationship between epigenetic remodeling and embryonic development has been gradually revealed. This review synthesizes recent advances in our understanding of the dynamics of epigenetic reprogramming during early embryogenesis in mice and humans. It covers the remodeling of DNA methylation, histone modifications, chromatin accessibility, and three-dimensional chromatin architecture, with a particular focus on the dynamic features of histone modifications. The patterns of common histone modifications such as methylation, acetylation, and ubiquitination are elaborated. Furthermore, the review outlines both the emerging roles of metabolism-associated modifications such as crotonylation and lactylation in genomic targeting and transcriptional regulation, and the dynamic patterns of histone variant incorporation.