title: Klf2 is an essential factor that sustains ground state pluripotency.
abstract: The maintenance of mouse embryonic stem cells (mESCs) requires LIF and serum. However, a pluripotent "ground state," bearing resemblance to preimplantation mouse epiblasts, can be established through dual inhibition (2i) of both prodifferentiation Mek/Erk and Gsk3/Tcf3 pathways. While Gsk3 inhibition has been attributed to the transcriptional derepression of Esrrb, the molecular mechanism mediated by Mek inhibition remains unclear. In this study, we show that Krüppel-like factor 2 (Klf2) is phosphorylated by Erk2 and that phospho-Klf2 is proteosomally degraded. Mek inhibition hence prevents Klf2 protein phosphodegradation to sustain pluripotency. Indeed, while Klf2-null mESCs can survive under LIF/Serum, they are not viable under 2i, demonstrating that Klf2 is essential for ground state pluripotency. Importantly, we also show that ectopic Klf2 expression can replace Mek inhibition in mESCs, allowing the culture of Klf2-null mESCs under Gsk3 inhibition alone. Collectively, our study defines the Mek/Erk/Klf2 axis that cooperates with the Gsk3/Tcf3/Esrrb pathway in mediating ground state pluripotency.
authors.affiliation: Genome Institute of Singapore, 60 Biopolis Street, #02-01 Genome Building, Singapore 138672, Singapore; School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive, Singapore 637551, Singapore.
authors.forename: Jia-Chi
authors.initials: JC
authors.lastname: Yeo
authors.affiliation: Genome Institute of Singapore, 60 Biopolis Street, #02-01 Genome Building, Singapore 138672, Singapore.
authors.forename: Jianming
authors.initials: J
authors.lastname: Jiang
authors.affiliation: Genome Institute of Singapore, 60 Biopolis Street, #02-01 Genome Building, Singapore 138672, Singapore; Department of Biological Sciences, National University of Singapore, 14 Science Drive 4, Singapore 117543, Singapore.
authors.forename: Zi-Ying
authors.initials: ZY
authors.lastname: Tan
authors.affiliation: Genome Institute of Singapore, 60 Biopolis Street, #02-01 Genome Building, Singapore 138672, Singapore.
authors.forename: Guo-Rong
authors.initials: GR
authors.lastname: Yim
authors.affiliation: Genome Institute of Singapore, 60 Biopolis Street, #02-01 Genome Building, Singapore 138672, Singapore.
authors.forename: Jia-Hui
authors.initials: JH
authors.lastname: Ng
authors.affiliation: Genome Institute of Singapore, 60 Biopolis Street, #02-01 Genome Building, Singapore 138672, Singapore.
authors.forename: Jonathan
authors.initials: J
authors.lastname: Göke
authors.affiliation: Genome Institute of Singapore, 60 Biopolis Street, #02-01 Genome Building, Singapore 138672, Singapore; Department of Biology, Clarkson University, Potsdam, NY 13699, USA.
authors.forename: Petra
authors.initials: P
authors.lastname: Kraus
authors.affiliation: Genome Institute of Singapore, 60 Biopolis Street, #02-01 Genome Building, Singapore 138672, Singapore.
authors.forename: Hongqing
authors.initials: H
authors.lastname: Liang
authors.affiliation: Genome Institute of Singapore, 60 Biopolis Street, #02-01 Genome Building, Singapore 138672, Singapore; Graduate School for Integrative Sciences and Engineering, National University of Singapore, Singapore 117456, Singapore.
authors.forename: Kevin Andrew Uy
authors.initials: KA
authors.lastname: Gonzales
authors.affiliation: School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive, Singapore 637551, Singapore.
authors.forename: Han-Chung
authors.initials: HC
authors.lastname: Chong
authors.affiliation: Genome Institute of Singapore, 60 Biopolis Street, #02-01 Genome Building, Singapore 138672, Singapore.
authors.forename: Cheng-Peow
authors.initials: CP
authors.lastname: Tan
authors.affiliation: Genome Institute of Singapore, 60 Biopolis Street, #02-01 Genome Building, Singapore 138672, Singapore.
authors.forename: Yee-Siang
authors.initials: YS
authors.lastname: Lim
authors.affiliation: School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive, Singapore 637551, Singapore; Institute of Molecular and Cell Biology, 61 Biopolis Drive, Proteos, A(∗)STAR, Singapore 138673, Singapore.
authors.forename: Nguan-Soon
authors.initials: NS
authors.lastname: Tan
authors.affiliation: Genome Institute of Singapore, 60 Biopolis Street, #02-01 Genome Building, Singapore 138672, Singapore; Department of Biology, Clarkson University, Potsdam, NY 13699, USA.
authors.forename: Thomas
authors.initials: T
authors.lastname: Lufkin
authors.affiliation: Genome Institute of Singapore, 60 Biopolis Street, #02-01 Genome Building, Singapore 138672, Singapore; School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive, Singapore 637551, Singapore; Department of Biological Sciences, National University of Singapore, 14 Science Drive 4, Singapore 117543, Singapore; Graduate School for Integrative Sciences and Engineering, National University of Singapore, Singapore 117456, Singapore; Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, Block MD6, Centre for Translational Medicine, 14 Medical Drive #14-01T, Singapore 117599, Singapore. Electronic address: nghh@gis.a-star.edu.sg.
authors.forename: Huck-Hui
authors.initials: HH
authors.lastname: Ng
mesh_terms: D000818:Animals; D002478:Cells, Cultured; D053595:Embryonic Stem Cells / Q000378:metabolism; D051741:Kruppel-Like Transcription Factors / Q000235:genetics / Q000378:metabolism*; D051379:Mice; D039904:Pluripotent Stem Cells / Q000166:cytology* / Q000378:metabolism*
chemical_list: C498314:Klf2 protein, mouse; D051741:Kruppel-Like Transcription Factors