2024-05-13 カリフォルニア工科大学(Caltech)
<関連情報>
- https://www.caltech.edu/about/news/fetal-cells-can-be-traced-back-to-the-first-day-of-embryonic-development
- https://www.cell.com/cell/fulltext/S0092-8674(24)00455-0
最初の2つの胚盤胞はヒト胚に不均等に寄与する The first two blastomeres contribute unequally to the human embryo
Sergi Junyent,Maciej Meglicki ,Roman Vetter,…,Richard J. Paulson,Dagmar Iber,Magdalena Zernicka-Goetz
Cell Published:May 13, 2024
DOI:https://doi.org/10.1016/j.cell.2024.04.029
Highlights
- Lineage tracing of human embryos from the 2-cell to the blastocyst stage
- The majority of the epiblast is derived from only one 2-cell stage blastomere
- Early asymmetric divisions are a bottleneck controlling the embryo’s clonal composition
- First-dividing 2-cell blastomere generates more asymmetric divisions at 8-cell stage
Summary
Retrospective lineage reconstruction of humans predicts that dramatic clonal imbalances in the body can be traced to the 2-cell stage embryo. However, whether and how such clonal asymmetries arise in the embryo is unclear. Here, we performed prospective lineage tracing of human embryos using live imaging, non-invasive cell labeling, and computational predictions to determine the contribution of each 2-cell stage blastomere to the epiblast (body), hypoblast (yolk sac), and trophectoderm (placenta). We show that the majority of epiblast cells originate from only one blastomere of the 2-cell stage embryo. We observe that only one to three cells become internalized at the 8-to-16-cell stage transition. Moreover, these internalized cells are more frequently derived from the first cell to divide at the 2-cell stage. We propose that cell division dynamics and a cell internalization bottleneck in the early embryo establish asymmetry in the clonal composition of the future human body.
Graphical abstract
