“…In mice, the ICM and epiblast cells of blastocysts, as well as the embryonic stem (ES) cell lines that are derived from them, are in the naive state. Naive pluripotency is associated with the expression of transcription factors Klf2, Klf4, Gbx2, Tfcp2l1, Esrrb, Tbx3, and Sall4 (Dunn et al, 2014), low DNA methylation (Leitch et al, 2013; Leitch et al, 2016), high mitochondrial respiration (Carbognin et al, 2016; Sone et al, 2017), and enrichment of active histone modifications at promoter regions of developmental genes (Hayashi et al, 2008). Formative pluripotency characterizes the epiblast cells of peri-implantation embryos, as well as the corresponding pluripotent stem cell lines, called formative stem (FS) cells (Kinoshita et al, 2020; Smith, 2017).…”