OCT4 and SOX2 Work as Transcriptional Activators in Reprogramming Human Fibroblasts

Cell Rep. 2017 Aug 15;20(7):1585-1596. doi: 10.1016/j.celrep.2017.07.071.

Abstract

SOX2 and OCT4, in conjunction with KLF4 and cMYC, are sufficient to reprogram human fibroblasts to induced pluripotent stem cells (iPSCs), but it is unclear if they function as transcriptional activators or as repressors. We now show that, like OCT4, SOX2 functions as a transcriptional activator. We substituted SOX2-VP16 (a strong activator) for wild-type (WT) SOX2, and we saw an increase in the efficiency and rate of reprogramming, whereas the SOX2-HP1 fusion (a strong repressor) eliminated reprogramming. We report that, at an early stage of reprogramming, virtually all DNA-bound OCT4, SOX2, and SOX2-VP16 were embedded in putative enhancers, about half of which were created de novo. Those associated with SOX2-VP16 were, on average, stronger than those bearing WT SOX2. Many newly created putative enhancers were transient, and many transcription factor locations on DNA changed as reprogramming progressed. These results are consistent with the idea that, during reprogramming, there is an intermediate state that is distinct from both parental cells and iPSCs.

Keywords: enhancers; iPSCs; reprogramming; stem cells; transcription; transcription factors.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, N.I.H., Extramural

MeSH terms

  • Cell Differentiation
  • Cellular Reprogramming*
  • Fibroblasts / cytology
  • Fibroblasts / metabolism*
  • Herpes Simplex Virus Protein Vmw65 / genetics
  • Herpes Simplex Virus Protein Vmw65 / metabolism
  • Humans
  • Induced Pluripotent Stem Cells / cytology
  • Induced Pluripotent Stem Cells / metabolism*
  • Kruppel-Like Transcription Factors / genetics
  • Kruppel-Like Transcription Factors / metabolism
  • Octamer Transcription Factor-3 / genetics*
  • Octamer Transcription Factor-3 / metabolism
  • Primary Cell Culture
  • Proto-Oncogene Proteins c-myc / genetics
  • Proto-Oncogene Proteins c-myc / metabolism
  • Recombinant Fusion Proteins / genetics*
  • Recombinant Fusion Proteins / metabolism
  • SOXB1 Transcription Factors / genetics*
  • SOXB1 Transcription Factors / metabolism
  • Signal Transduction
  • Transcriptional Activation

Substances

  • GKLF protein
  • Herpes Simplex Virus Protein Vmw65
  • Kruppel-Like Transcription Factors
  • MYC protein, human
  • Octamer Transcription Factor-3
  • POU5F1 protein, human
  • Proto-Oncogene Proteins c-myc
  • Recombinant Fusion Proteins
  • SOX2 protein, human
  • SOXB1 Transcription Factors