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 Sorting 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 Sorting 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 primitive endoderm (PrE). In mid-blastocysts, Epi and PrE cells are intermingled; however, as development proceeds to the late-blastocyst stage, Cell Sorting occurs whereby cells of the same lineage assemble. As a result, Epi cells accumulate at one side of the ICM, while PrE cells migrate outward to form a layer overlying the Epi. Cell competition simultaneously eliminates cells with lower expression of pluripotency factors through apoptosis, and suppression of this apoptosis disrupts the proper arrangement of Epi and PrE, suggesting that apoptosis is required for correct Cell Sorting (Hashimoto & Sasaki, Dev Cell 2019). However, the cell behaviors underlying Epi and PrE sorting, and how apoptosis influences the movements of neighboring cells, remain incompletely understood.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.
