H3K27me3 at pericentromeric heterochromatin is a defining feature of the early mouse blastocyst.

Early mouse development is characterized by structural and epigenetic changes while cells progress towards differentiation. At blastocyst stage, the segregation of the three primordial lineages is accompanied by establishment of differential patterns of DNA methylation and post-translational modifications of histones, such as H3K27me3. Here, we analysed the dynamics of H3K27me3 at pericentromeric heterochromatin (PCH) during early development.

Transcription of rRNA in early mouse embryos promotes chromatin reorganization and expression of major satellite repeats.

During the first cell cycles of early development, the chromatin of the embryo is highly reprogrammed while the embryonic genome starts its own transcription. The spatial organization of the genome is an important process that contributes to regulating gene transcription in time and space. It has, however, been poorly studied in the context of early embryos.

Three-dimensional analysis of nuclear heterochromatin distribution during early development in the rabbit.

Changes to the spatial organization of specific chromatin domains such as constitutive heterochromatin have been studied extensively in somatic cells. During early embryonic development, drastic epigenetic reprogramming of both the maternal and paternal genomes, followed by chromatin remodeling at the time of embryonic genome activation (EGA), have been observed in the mouse. Very few studies have been performed in other mammalian species (human, bovine, or rabbit) and the data are far from complete.

Prosurvival effect of cumulus prostaglandin G/H synthase 2/prostaglandin2 signaling on bovine blastocyst: impact on in vivo posthatching development.

Apoptotic activity is a common physiological process which culminates at the blastocyst stage in the preimplantation embryo of many mammals. The degree of embryonic cell death can be influenced by the oocyte microenvironment. However, the prognostic significance of the incidence of apoptosis remains undefined.