Genome-wide screen of promoter methylation analysis of ES cells and ES derived epidermal-like cells.

Embryonic stem cells (ESCs) are a population of pluripotent cells which can differentiate into different cell types. However, there are few reports with regard to differentiate ESCs into epidermal cells in vitro. In this study, we aimed to investigate differentially methylated promoters involved in process of differentiation from ESCs into epidermal-like cells (ELCs) induced by human amnion. We successfully induced ESCs into ELCs, which expressed the surface markers of CK19, CK15 and β1-integrin. With MeDIP-chip arrays, we identified 3435 gene promoters to be differentially methylated, involving 894 HCP (high CpG-containing promoter), 974 ICP (intermediate CpG-containing promoter) and 1567 LCP (low CpG-containing promoter) among all the 17,500 DNA methylation regions of gene promoters in both ESCs and ELCs. Gene oncology and pathway analysis demonstrated that these genes were involved in all the three categories of GO enrichment analysis, including biological process, molecular function and cellular component. All these data suggested that embryonic stem cells can differentiate into epidermal-like cells and promoter methylation is of great importance in this process.