Capturing totipotent-like 8-cell states in vitro with re-activation of endogenous retrovirus HERVL [RNA-seq]

Although recent protocols have enabled induction of 8-cell-like cells (8CLCs) from human pluripotent stem cells (hPSCs), their inherent heterogeneity and the lack of specific markers for authentic totipotent-like states have impeded the isolation of pure populations and limited mechanistic studies.

To address this, we leveraged the specific activation of an 8-cell-stage endogenous retrovirus HERVL to establish a HERVL-tdTomato/TPRX1-GFP dual-reporter hPSC line. This system enables real-time monitoring and precise isolation of bona fide 8CLCs induced from primed hPSCs. Intriguingly, we demonstrate that the previously utilized TPRX1 reporter marks an intermediate population that subsequently transitions into HERVL-positive 8CLCs, capturing a transcriptional identity closely resembling in vivo 8-cell embryos.