Analysis of Porcine Trophoblast Stem Cells from Cloned Blastocysts Based on Transcriptome and DNA Methylome Sequencing

Nuclear transfer is an effective strategy to multiply pigs with desired traits. However, most cloned porcine embryos are lost because of placental abnormalities. Insights into the molecular pathways controlling placental development may be gained by using porcine trophoblast stem cells (pTSCs) that can self-renew and differentiate into various placental cell types . In this study, we succeeded in establishing pTSCs from fertilized blastocysts with higher derivation efficiency than from cloned blastocysts. Six total RNA samples from this two sources of pTSCs were used to analyze the transcriptome difference. The sequence data analysis showed a significant difference in the mRNA expression quantity of pluripotency-related genes, pTSCs specific transcriptional factors, some imprinted genes and X-linked genes between the two groups. Moreover, higher expression lever of placenta development-related genes in cloned pTSCs indicate it propose to differentiate. The epigenetic modifier such as DNA methyltransferase and histone demethylase genes also show abnormal expression in cloned group. We are analyzing the DNA methylomes of pTSCs by using whole-genome bisulfite sequencing. These existing results showed that different genes may be involved in the abnormal phenotypes of cloned trophoblasts and that the use of pTSCs may help to unravel the epigenetic defects affecting development of clones.