Abstract：DNA methylation is one of the most important epigenetic markers, which has been well characterized and demonstrated to be involved in many biological processes, including transposable element silencing, genomic imprinting and X chromosome inactivation etc. Yamanaka reprogrammed the mouse(Mus musculus) fibroblasts back to a pluripotent state via ectopically expressing four embryonically special transcription factors Oct4, Sox2, Klf4 and c-Myc, and named the cells as induced pluripotent stem cells (iPSCs). During reprogramming, there was accompanied with a series of epigenetic changes, so iPSCs can be used as a useful tool to study the interplay of epigenetic modifications and dynamics. In this study, porcine(Sus scrofa) fetal fibroblasts were isolated from 35-day-old fetus, and were reprogrammed into iPSCs using classical four factors recombination, namely Oct4, Sox2, Klf4 and c-Myc. The pluripotent markers of colonies were identified by immunofluorescence staining. With the method of bisulphate treatment, methylation status of promoters in endogenous pluripotent genes Oct4, Sox2, Klf4 and c-Myc were detected. It was found that the methylation status were very low which indicated that it was accompanied by decreased methylation status in promoters during the reprogramming of somatic cells into iPSCs. Therefore, this study is helpful to understand the DNA demethylation of pluripotency gene, and provides further insight into epigenetic regulations that control the pluripotency genes expression during reprogramming.
