Epigenetic regulation of Nanog gene in embryonic stem and trophoblast stem cells

Genes Cells. 2007 Mar;12(3):387-96. doi: 10.1111/j.1365-2443.2007.01058.x.

Abstract

The Nanog and Oct-4 genes are essential for maintaining pluripotency of embryonic stem (ES) cells and early embryos. We previously reported that DNA methylation and chromatin remodeling underlie the cell type-specific mechanism of Oct-4 gene expression. In the present study, we found that there is a tissue-dependent and differentially methylated region (T-DMR) in the Nanog up-stream region. The T-DMR is hypomethylated in ES cells, but is heavily methylated in trophoblast stem (TS) cells and NIH/3T3 cells, in which the Nanog gene is repressed. Furthermore, in vitro methylation of T-DMR suppressed Nanog promoter activity in reporter assay. Chromatin immunoprecipitation assay revealed that histone H3 and H4 are highly acetylated, and H3 lysine (K) 4 is hypermethylated at the Nanog locus in ES cells. Conversely, histone deacetylation and H3-K4 demethylation occurred in TS cells. Importantly, in TS cells, hypermethylation of H3-K9 and -K27 is found only at the Nanog locus, not the Oct-4 locus, indicating that the combination of histone modifications associated with the Nanog gene is distinct from that of the Oct-4 gene. In conclusion, the Nanog gene is regulated by epigenetic mechanisms involving DNA methylation and histone modifications.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • 5' Flanking Region
  • Acetylation
  • Animals
  • Azacitidine / analogs & derivatives
  • Azacitidine / pharmacology
  • Base Sequence
  • Cell Line
  • DNA Methylation
  • DNA Primers / genetics
  • DNA-Binding Proteins / genetics*
  • Decitabine
  • Embryonic Stem Cells / metabolism*
  • Epigenesis, Genetic* / drug effects
  • Histones / metabolism
  • Homeodomain Proteins / genetics*
  • Hydroxamic Acids / pharmacology
  • Mice
  • Mice, Inbred C57BL
  • NIH 3T3 Cells
  • Nanog Homeobox Protein
  • Octamer Transcription Factor-3 / genetics
  • Pluripotent Stem Cells / metabolism
  • Promoter Regions, Genetic
  • Trophoblasts / cytology
  • Trophoblasts / metabolism

Substances

  • DNA Primers
  • DNA-Binding Proteins
  • Histones
  • Homeodomain Proteins
  • Hydroxamic Acids
  • Nanog Homeobox Protein
  • Nanog protein, mouse
  • Octamer Transcription Factor-3
  • trichostatin A
  • Decitabine
  • Azacitidine