A Tale of Division and Polarization in the Mammalian Embryo.
Srinivas S., Rodriguez TA.
The first cell fate choice in mouse development is the segregation of the embryonic inner cell mass and the extra-embryonic trophectoderm. In this issue of Developmental Cell, Korotkevic and colleagues (2017) show that the interplay between cell polarization and cell-cell contact drives the segregation of these lineages, providing a framework for self-organization in development.