title: Reprogramming factor stoichiometry influences the epigenetic state and biological properties of induced pluripotent stem cells.
abstract: We compared two genetically highly defined transgenic systems to identify parameters affecting reprogramming of somatic cells to a pluripotent state. Our results demonstrate that the level and stoichiometry of reprogramming factors during the reprogramming process strongly influence the resulting pluripotency of iPS cells. High expression of Oct4 and Klf4 combined with lower expression of c-Myc and Sox2 produced iPS cells that efficiently generated "all-iPSC mice" by tetraploid (4n) complementation, maintained normal imprinting at the Dlk1-Dio3 locus, and did not create mice with tumors. Loss of imprinting (LOI) at the Dlk1-Dio3 locus did not strictly correlate with reduced pluripotency though the efficiency of generating "all-iPSC mice" was diminished. Our data indicate that stoichiometry of reprogramming factors can influence epigenetic and biological properties of iPS cells. This concept complicates efforts to define a "generic" epigenetic state of iPSCs and ESCs and should be considered when comparing different iPS and ES cell lines.
authors.affiliation: Whitehead Institute for Biomedical Research, Massachusetts Institute of Technology, Cambridge, MA 02142, USA.
authors.forename: Bryce W
authors.initials: BW
authors.lastname: Carey
authors.forename: Styliani
authors.initials: S
authors.lastname: Markoulaki
authors.forename: Jacob H
authors.initials: JH
authors.lastname: Hanna
authors.forename: Dina A
authors.initials: DA
authors.lastname: Faddah
authors.forename: Yosef
authors.initials: Y
authors.lastname: Buganim
authors.forename: Jongpil
authors.initials: J
authors.lastname: Kim
authors.forename: Kibibi
authors.initials: K
authors.lastname: Ganz
authors.forename: Eveline J
authors.initials: EJ
authors.lastname: Steine
authors.forename: John P
authors.initials: JP
authors.lastname: Cassady
authors.forename: Menno P
authors.initials: MP
authors.lastname: Creyghton
authors.forename: G Grant
authors.initials: GG
authors.lastname: Welstead
authors.forename: Qing
authors.initials: Q
authors.lastname: Gao
authors.forename: Rudolf
authors.initials: R
authors.lastname: Jaenisch
mesh_terms: D000818:Animals; D015415:Biomarkers / Q000378:metabolism; D002460:Cell Line; D065150:Cellular Reprogramming / Q000502:physiology*; D044127:Epigenesis, Genetic; D057026:Induced Pluripotent Stem Cells / Q000166:cytology / Q000502:physiology*; D000090062:Kruppel-Like Factor 4; D051741:Kruppel-Like Transcription Factors / Q000235:genetics / Q000378:metabolism; D008297:Male; D051379:Mice; D008822:Mice, Transgenic; D050814:Octamer Transcription Factor-3 / Q000235:genetics / Q000378:metabolism; D019076:Transgenes
chemical_list: D015415:Biomarkers; C000715468:Klf4 protein, mouse; D000090062:Kruppel-Like Factor 4; D051741:Kruppel-Like Transcription Factors; D050814:Octamer Transcription Factor-3; C494174:Pou5f1 protein, mouse