The transcription factor Gbx2 induces expression of Kruppel-like factor 4 to maintain and induce naive pluripotency of embryonic stem cells — The transcription factor Gbx2 induces expression of Kruppel-like factor 4 to maintain and induce naïve pluripotency of embryonic stem cells — Gbx2 promotes mESC self-renewal via inducing Klf4