FBS Colloquia No.345Laboratory for Embryogenesis

Live imaging analysis of the dynamics of cell competition and cell fate determinations in mice preimplantation embryos

During mice preimplantation embryo development, ICM cells differentiate into two types of cells, epiblast (Epi) and primitive endoderm (PrE) in the blastocyst stage. Cell proliferation, differentiation, and cell death occur simultaneously and epiblast, expressing high levels of pluripotent factors, are gathered, and surrounded by PrE. ICM cells express various levels of pluripotent factors at first and loser cells, expressing low levels of pluripotent factors, are eliminated by cell-cell interactions, called cell-competition. After that, only about ten epiblasts remain as a winner. This process is strictly regulated temporally and spatially; however, detailed mechanisms remain unknown. To reveal the mechanism, we visualized the dynamics of expressions of pluripotent factors in ICM cells during cell fate determinations and cell competition. We measured the change in pluripotent factor expressions and cell positions in the ICM over time and tried to elucidate the differences in the expression dynamics of these factors and cell movements between winners and losers.