FBS Colloquia No.404Laboratory for Embryogenesis
| Seminar or Lecture |
Analysis of the Dynamics of Unfit Cells Remaining in Mouse Preimplantation Embryos Rui Shibata [Graduate Student (D5/D5), Laboratory for Embryogenesis] Elucidating the biological significance of cell death in cell migration during pre-implantation mouse embryonic development Kazuki Kusumi [Graduate Student (D2/D5), Laboratory for Embryogenesis] |
|---|---|
| Date and Time | 23 Dec. 2025 (Tue), 12:15～13:00 |
| Place | 2F Seminar Room, BioSystems Building |
| Language | Japanese |
| Contact |
Toshihiro Aramaki (Assistant Professor) |
Analysis of the Dynamics of Unfit Cells Remaining in Mouse Preimplantation Embryos
In the mouse preimplantation embryo, the pluripotent epiblast is established. Because the epiblast consists of a small number of cells, the high quality of every cell is considered crucial for subsequent embryonic development. Our laboratory has previously shown that, during epiblast formation, cells with low expression of pluripotency factors, referred to as unfit cells, are eliminated through apoptosis mediated by cell–cell interactions. As a result, the epiblast is composed exclusively of cells with high expression of pluripotency factors. However, when the quality control mechanism is inhibited, these unfit cells can remain in the embryo, and their subsequent developmental fates have not been characterized. Thus, the physiological significance of this quality control system remains unclear. In this colloquium, I will present our detailed analysis of the developmental trajectories of unfit cells that persist in apoptosis-suppressed embryos.
Elucidating the biological significance of cell death in cell migration during pre-implantation mouse embryonic development
During the blastocyst stage of pre-implantation mouse development, the inner cell mass (ICM) differentiates into the epiblast (Epi) and the primitive endoderm (PrE). At the mid-blastocyst stage, Epi and PrE cells are intermingled, but as development progresses toward the late-blastocyst stage, PrE cells undergo directed migration to form a continuous layer overlying the Epi. During this process, cell competition occurs simultaneously, in which cells with lower levels of pluripotency factors are eliminated through apoptosis. Suppressing apoptosis induced by such cell competition disrupts the proper spatial arrangement of Epi and PrE, suggesting that apoptosis driven by cell competition is required for correct lineage sorting. However, many aspects remain unclear regarding how Epi and PrE cells migrate within the embryo and how surrounding cells behave before and after cell death. In this colloquium, I will present ongoing live-imaging analyses examining the dynamics of Epi and PrE in normal embryos, as well as changes in cell migration that occur when cell death is suppressed.
