Blastocyst cavity expansion promotes DNA methylation during early development of mouse embryos

Abstract

DNA methylation is an important epigenetic modification that plays a key role in the complex process of mouse embryonic development. The blastocyst cavity expansion is crucial during the second cell fate specification in mouse embryos, yet its impact on DNA methylation remains unclear. In this study, we investigate the effects of blastocyst cavity expansion on DNA methylation through two different methods: hypertonic exposure or disruption of TE (Trophectoderm) cortical tension. We found that inhibition of the blastocyst cavity expansion, either through hypertonic exposure or through disruption of TE cortical tension, suppresses the level of 5 ​MC (5-Methylcytosine) marker of DNA methylation. As a key upstream regulator of 5 ​MC, the expression variance of DNMT3L (DNA methyltransferase 3-like protein) is similar to that of 5 ​MC during the embryonic stages E2.5 to E3.5. This study reveals the function of mechanical behavior of embryos in the epigenetic modification of early mammalian embryos.