Cell shape dynamics during mouse peri-implantation development and embryo dormancy

The mammalian embryo establishes the first direct contact with the maternal tissues during implantation. As the blastocyst attaches to the uterine wall, it initiates transformation into a post-implantation conceptus, laying the foundations for placentation and foetal development. The peri-implantation embryogenesis relies on the coordinated growth, morphogenesis, and cell fate transitions of the embryonic and extra-embryonic tissues, entailing changes in cell shape and tissue architecture. In some species, including mice, this process is suspended in a non-receptive uterine environment, where embryonic development arrests at the blastocyst stage and the embryo enters a dormant state known as diapause. However, despite being dormant, relatively slow morphogenetic changes continue to reshape the embryonic cells. Here, we will briefly review the process of murine blastocyst formation before focusing primarily on cell shape and tissue dynamics during peri-implantation embryogenesis. Finally, we will synthesise the current knowledge on tissue morphogenesis during embryo dormancy.