Table 2.

Proteins implicated in reversion of EpiSCs to a mESC-like state

Protein	Tissue distribution	Gain-of-function or loss-of function phenotype in mice/ESCs	Reversion mouse background	Reversion culture condition	Reversion tissue origin	Refs
LIF/STAT3		Gp130 knockout eliminates capacity for diapause; Stat3 activation significantly enhances EpiSC reversion to naïve pluripotency	129	LIF/serum	Postimplantation epiblast	Bao et al., 2009; Yang et al., 2010; All LIF/2i papers
FGF/ERK	Nearly ubiquitous signaling pathway	Fgf4-null or Erk2-null ES cells blocked lineage commitment;	129, NOD	N2B27-LIF/2i; KSR-LIF/2i	In vitro-derived EpiSC; Embryo-derived EpiSC	Kunath et al., 2007; Stavridis et al., 2007; All LIF/2i papers
WNT/GSK3-Beta	Nearly ubiquitous signaling pathway	Promotes self-renewal of mESCs/hESCs; GSK3 inhibition in combination with ERK inhibition allows efficient derivation of naïve mESCs	129, NOD	N2B27-LIF/2i; KSR-LIF/2i		Sato et al., 2004; Ying et al., 2008; Ten Berge et al., 2011; All LIF/2i papers;
Klf4	High expression in gut; Highly expressed in naïve ESCs	Overexpression sustains LIF-independent self-renewal	129, NOD	N2B27-LIF/2i	In vitro-derived EpiSC; iEpiSC; NOD ICM outgrowth; NOD EpiSC	Guo et al., 2009; Hanna et al., 2009; Han et al., 2011
C-Myc	Highly expressed in proliferating cells	Overexpression sustains LIF-independent self-renewal	129, NOD	N2B27-LIF/2i	NOD ICM outgrowth; NOD EpiSC	Cartwright et al., 2005; Hanna et al., 2009
Nanog	Inner cell mass, germ cells; Highly expressed in naïve ESCs	In vivo knockout ICM fails to form; conditional knockout increases ES cell propensity for differentiation; Overexpression in mESCs sustains LIF-independent self-renewal; overexpression in EpiSCs reverts mESCs to pluripotency	129	N2B27-LIF/2i	In vitro-derived EpiSC	Silva et al, 2009
Klf2	High expression in lung; Highly expressed in naïve ESCs	Overexpression in mESCs sustains LIF-independent self-renewal; Knockdown reduces efficiency of EpiSC reversion to naïve pluripotency; replacement of exogenous Klf4 for somatic cell reprogramming	129	N2B27-LIF/2i	In vitro-derived EpiSC	Hall et al, 2009
Nr5a1	High expression in adrenal tissues	Overexpression reverts EpiSCs to naïve pluripotency; replacement of exogenous Oct4 for somatic cell reprogramming	129	N2B27-LIF/2i	In vitro-derived EpiSC	Guo et al, 2010
Nr5a2	High expression in liver cells; Expressed in naïve ESCs	Overexpression reverts EpiSCs to naïve pluripotency; replacement of exogenous Oct4 for somatic cell reprogramming	129	N2B27-LIF/2i	In vitro-derived EpiSC	Guo et al, 2010; Heng et al, 2010

	Mouse background	Donor cell type	TF transfection?	Transgene delivery method	Transgene	Culture conditions	Naïve pluripotency
Guo et al., 2009	129	EpiSC	Yes	PiggyBac	Klf4	N2B27-LIF-PD03/CH	Yes
Hanna et al., 2009	NOD	ICM outgrowth	Yes	FUW-Ubc or FUW-tetO	Klf4/Cmyc	Serum + LIF	Yes
Hanna et al., 2009	NOD	EpiSC	Yes	FUW-Ubc or FUW-tetO	Klf4/Cmyc	Serum + LIF	Yes
Hanna et al., 2009	NOD	ICM outgrowth	No			PD/CH or KP/CH	Yes
Hanna et al., 2009	NOD	EpiSC	No			PD/CH or KP/CH	Yes
Silva et al., 2009	129	EpiSC	Yes	PiggyBac	Nanog	PD/CH	Yes
Bao et al., 2009	129	Postimplantationepiblast	No			LIF/serum	Yes
Hall et al., 2009	129	EpiSC	Yes	PiggyBac	Klf2	PD/CH	Yes
Greber et al., 2010	129	EpiSC	No			KSR-PD/CH	Yes
Han et al., 2011	129	iEpiSC	Yes	Lentivirus	Klf4		Yes
Yang et al., 2010	129	EpiSC	Yes	PiggyBac	Stat3	PD/CH	Yes
Guo et al., 2010	129	EpiSC	Yes	PiggyBac	Nr5a1	PD/CH	Yes