Identification of amnion progenitor-like cells at the amnion-epiblast boundary in the primate peri-gastrula

Amniogenesis is triggered in a collection of pluripotent epiblast cells as the human embryo implants. To gain insights into the critical but poorly understood transcriptional machinery governing amnion fate determination, we examined the evolving transcriptome of a developing human pluripotent stem cell-derived amnion model at the single cell level. This analysis revealed a previously unrecognized CLDN10+ amnion progenitor cell type and enabled the identification of several markers specific to the different stages of lineage progression. Strikingly, we found that expression of CLDN10 is restricted to the amnion-epiblast boundary region in peri-gastrula cynomolgus macaque embryos, bolstering the notion that, at this stage, the amnion-epiblast boundary is a site of active amniogenesis. Bioinformatic analysis of published primate peri-gastrula single cell sequencing data further confirmed that CLDN10 is expressed in cells progressing to amnion. Overall, this study identifies a previously unrecognized CLDN10+ amnion progenitor-like cell population and validates the presence of these fate transitioning cells at the boundary of the developing amnion. ### Competing Interest Statement The authors have declared no competing interest.