Extraembryonic gut endoderm cells undergo programmed cell death during development (RNA-seq)

Despite a distinct developmental origin, extraembryonic cells in mice contribute to gut endoderm and converge to transcriptionally resemble their embryonic counterparts. Notably, extraembryonic progenitors share a non-canonical epigenome, raising several pertinent questions, including whether this landscape is reset to match the embryonic regulation and if these cells persist into later development. Here, we developed a two-color lineage tracing strategy to track and isolate extraembryonic cells over time. We find that extraembryonic gut cells display substantial memory of their developmental origin including retention of their original DNA methylation landscape and resulting transcriptional signatures. Furthermore, we show that extraembryonic gut cells undergo programmed cell death and neighboring embryonic cells clear their remnants via non-professional phagocytosis. By midgestation, we no longer detect extraembryonic cells in the wild type gut while they persist and differentiate further in p53 mutant embryos. Our study provides key insights into the molecular and developmental fate of extraembryonic cells inside the embryo.