Derivation of ground-state female ESCs maintaining gamete-derived DNA methylation

Inhibitors of MEK1/2 and Gsk3b, known as '2i' culture conditions, enhance the derivation of embryonic stem cells (ESCs) and promote ground-state pluripotency in rodents 1,2. Here we show that the derivation of female mouse ESCs in the presence of 2i (2i-ESCs) results in a widespread loss of DNA methylation including a massive erasure of genomic imprints. Despite this global loss of DNA methylation, the early-passage 2i-ESCs efficiently differentiate into somatic cells and this process requires genome-wide de novo DNA methylation. However, the majority of imprinting control regions (ICRs) remain unmethylated in the 2i-ESC-derived differentiated cells. Consistently, 2i-ESCs exhibit impairment of autonomous embryonic and placental development by tetraploid embryo complementation and nuclear transplantation. We identified the derivation conditions of female ESCs that display 2i-ESC-like transcriptional signatures while preserving gamete-derived DNA methylation and autonomous developmental potential. Upon prolonged culture, however, female ESCs exhibit ICR demethylation, regardless of culture conditions. Our results provide insights into derivation of female ESCs reminiscent of ICM of preimplantation embryos. S-ESCs are ESCs established under serum-containing medium. 2i_S_ESCs are ESCs established in 2i-containing medium, followed by maintenance in serum-containing medium. Overall design: Analyzing DNA methylation profiles and transcriptional profiles in 2i-ESCs, 2i-S-ESCs, 2i-MEFs, S-ESCs, t2i-ESCs, a2i-ESCs and MEFs for molecular analysis and 2n/4n injection and nuclear transfer for developmental assay for ESCs.