美国加州理工学院Magdalena Zernicka-Goetz研究团队发现，前两个卵裂球对人类胚胎的贡献不均等。该研究于2024年5月13日在线发表于国际一流学术期刊《细胞》。

研究人员利用实时成像、非侵入性细胞标记和计算预测对人类胚胎进行了前瞻性谱系追踪，以确定每个2细胞期卵裂球对上胚层（身体）、下胚层（卵黄囊）和滋养层（胎盘）的贡献。研究人员发现，大多数上胚层细胞只来源于2细胞期胚胎的一个卵裂球。研究人员观察到，只有一到三个细胞在8-16个细胞阶段过渡时被内化。

此外，这些内化的细胞更多来自2细胞期第一个分裂的细胞。研究人员认为，早期胚胎中的细胞分裂动力学和细胞内化瓶颈决定了未来人体克隆组成的不对称性。

据悉，根据对人类谱系的回顾性重建预测，体内克隆的严重失衡可追溯到2细胞阶段的胚胎。然而，这种克隆不对称是否以及如何在胚胎中产生尚不清楚。

附：英文原文

Title: The first two blastomeres contribute unequally to the human embryo

Author: Sergi Junyent, Maciej Meglicki, Roman Vetter, Rachel Mandelbaum, Catherine King, Ekta M. Patel, Lisa Iwamoto-Stohl, Clare Reynell, Dong-Yuan Chen, Patrizia Rubino, Nabil Arrach, Richard J. Paulson, Dagmar Iber, Magdalena Zernicka-Goetz

Issue&Volume: 2024-05-13

Abstract: 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.

DOI: 10.1016/j.cell.2024.04.029

Source: https://www.cell.com/cell/fulltext/S0092-8674(24)00455-0