Lineage specification and pluripotency revealed by transcriptome analysis from oocyte to blastocyst in pig

The inner cell mass in blastocyst is the origin of all the somatic and germ cells in mammals, and of pluripotent stem cells in vitro. As the conserved principles between pig and human, here we performed comprehensive single-cell RNA-seq for porcine early embryos from oocyte to early blastocyst. We show the specification of inner cell mass and trophectoderm in morula, and the molecular signature of the precursors. We demonstrate the existence of naïve pluripotency signature in morula and inner cell mass of early blastocyst, and the specific pluripotent genes and the activity of signalling pathways highlight the characteristics of the naïve pluripotency. We observe absence of dosage compensation with respect to X-chromosome in morula, and incomplete dosage compensation in early blastocyst. However, the dynamics of dosage compensation may be independent on the expression of XIST induced X-chromosome inactivation. Our study describes molecular landmarks of embryogenesis in pig that will provide a better strategy for derivation of porcine pluripotent stem cells and improve the research in regenerative medicine.