
Cell Reports, Journal Year: 2025, Volume and Issue: 44(4), P. 115568 - 115568
Published: April 1, 2025
The specification of extra-embryonic mesenchyme (ExMC) is a prime example developmental divergence between mouse and human. Derived from definitive mesoderm during gastrulation, the human ExMC first appears at peri-implantation prior to gastrulation therefore its cellular origin, still unknown, must differ. In pluripotent stem cell model, we report that shares progenitor cells with trophoblast, suggesting trophectoderm origin. This ability form extend trophoblast lines. We define HAND1 as an essential regulator specification, null remaining in lineage. Bound by HAND1, ape-specific, endogenous retrovirus-derived LTR2B contributes unique features ExMC. Additionally, supports maintenance cells, possibly reflecting role maintaining epiblast pluripotency through development. Our data emphasize nascent evolutionary innovation early development provide system study this.
Language: Английский