Epigenetic dynamics during preimplantation development

Abstract

Successful mammalian development requires descendants of single-cell zygotes to differentiate into diverse cell types even though they contain the same genetic material. Preimplantation dynamics are first driven by the necessity of reprogramming haploid parental epigenomes to reach a totipotent state. This process requires extensive erasure of epigenetic marks shortly after fertilization. During the few short days after formation of the zygote, epigenetic programs are established and are essential for the first lineage decisions and differentiation. Here we review the current understanding of DNA methylation and histone modification dynamics responsible for these early changes during mammalian preimplantation development. In particular we highlight insights that have been gained through next generation sequencing technologies comparing human embryos to other models as well as the recent discoveries of active DNA demethylation mechanisms at play during preimplantation.

Oocyte aging-induced Neuronatin (NNAT) hypermethylation affects oocyte quality by impairing glucose transport in porcine

“…This process is highly involved in many events during early embryo preimplantation development, including maternal-to–zygotic transition (MZT), compaction and the first two distince cell lineages (inner cell mass (ICM) and trophectoderm (TE)). Abnormal epigenetic modification, like impairing DNA methylation of imprinted genes, induces the damage to embryo and leads to deleterious influence on the development of embryos25. In our studies, we found that oocyte aging disturbed the expression of several imprinted genes dramatically and parthenogenetic blastocyst percentage from aged oocytes was significantly decreased (Fig.…”

Towards Functional Annotation of the Preimplantation Transcriptome: An RNAi Screen in Mammalian Embryos

“…Well-defined gene expression patterns occur within these two distinct lineages. For example, in the mouse embryo, the transcription factor Oct4 (also known as Pou5f1) is enriched in ICM and functions to promote pluripotency and inhibit differentiation, while the transcription factor Cdx2 becomes highly expressed in TE and influences epithelial differentiation91011. Appropriate regulation and mutually exclusive localization of Oct4 and Cdx2 is critical for successful ICM/TE lineage separation and formation of a competent blastocyst12131415.…”

Polyamide Nanogels from Generally Recognized as Safe Components and Their Toxicity in Mouse Preimplantation Embryos

“…54 Preimplantation embryos are highly sensitive to environmental changes and perturbations which can impair the dynamic morphogenetic events resulting in failure of blastocyst formation and/or long-term embryo survival. 54–56 It has been suggested that preimplantation embryos are generally more sensitive to toxicants than somatic cells. 57–58 We therefore assessed development of embryos in the presence of nanogels.…”