Derivation and characterization of chimera competent eXtra Embryonic eNdoderm (XEN) cells from pig blastocysts

We report for the first time, the derivation and characterization of extra-embryonic endoderm (XEN) cells from primitive endoderm (PrE) of porcine (p) embryos. The pXEN cells can be reliably and reproducibly generated from in vitro, in vivo and parthenote embryos, and expressed canonical PrE- and XEN-specific markers (GATA4, GATA6, SOX17, SALL4, FOXA2, and HNF4A). Transcriptome analysis of pXEN cells confirmed their XEN cell origin. When injected into blastocyst stage embryo, the pXEN cells contributed to wide-spread chimerism including visceral yolk sac, chorion, as well as embryonic gut and liver primordium in the fetus. The pXEN cells were shown to be an efficient nuclear donor for generating cloned offspring. Taken together, pXEN cells fulfill a longstanding need for a stable, chimera-competent, and nuclear transfer-compatible porcine embryonic cell line with applications for genome editing in livestock.