Epigenetic landscape of pluripotent stem cells.

SIGNIFICANCE: Derived from the inner cell mass of the preimplantation embryo, embryonic stem cells are prototype pluripotent stem (PS) cells that have the ability of self-renewal and differentiation into almost all cell types. Exploration of the mechanisms governing this pluripotency is important for understanding reprogramming mechanisms and stem cell behavior of PS cells and can lead to enhancing reprogramming efficiency and other applications. RECENT ADVANCES: Induced pluripotent stem cells are recently discovered PS cells that can be derived from somatic cells by overexpression of pluripotency-related transcription factors. Recent studies have shown that transcription factors and their epigenetic regulation play important roles in the generating, maintaining, and differentiating these PS cells. Recent advances in sequencing technologies allow detailed analysis of target epigenomes and microRNAs (miRs), and have revealed unique epigenetic marks and miRs for PS cells. CRITICAL ISSUES: Epigenetic modifications of genes include histone modifications, DNA methylation, and chromatin remodeling. Working closely with epigenetic modifiers, miRs play an important role in inducing and maintaining pluripotency. FUTURE DIRECTIONS: The dynamic changes in epigenetic marks during reprogramming and their role in cell fate changes are being uncovered. This review focuses on these new advances in the epigenetics of PS cells.