Overexpression Nanog activates pluripotent genes in porcine fetal fibroblasts and nuclear transfer embryos.

Nanog as an important transcription factor plays a pivotal role in maintaining pluripotency and in reprogramming the epigenome of somatic cells. Its ability to function on committed somatic cells and embryos has been well defined in mouse and human, but rarely in pig. To better understand Nanog's function on reprogramming in porcine fetal fibroblast (PFF) and nuclear transfer (NT) embryo, we cloned porcine Nanog CDS and constructed pcDNA3.1 (+)/Nanog and pEGFP-C1/Nanog overexpression vectors and transfected them into PFFs. We studied the cell biological changes and the expression of Nanog, Oct4, Sox2, Klf4, C-myc, and Sall4 in transfected PFFs. We also detected the development potential of the cloned embryos harboring Nanog stably overexpressed fibroblasts and the expression of Oct4, Sox2, and both endogenous and exogenous Nanog in these embryos. The results showed that transient overexpression Nanog in PFF could activate the expression of Oct4 (5-fold), C-myc (2-fold), and Sall4 (5-fold) in somatic cells, but they could not be maintained during G418 selection. In NT embryos, although Nanog overexpression did not have a significant effect on blastocyst development rate and blastocyst cell number, it could significantly activate the expression of endogenous Nanog, Oct4, Sox2 to 160-fold, 93-fold, and 182-fold, respectively (P < 0.05). Our results demonstrate that Nanog could interact with and activate other pluripotent genes both in PFFs and embryos.