GADD45a physically and functionally interacts with TET1

Differentiation. Jul-Oct 2015;90(1-3):59-68. doi: 10.1016/j.diff.2015.10.003. Epub 2015 Nov 3.

Abstract

DNA demethylation plays a central role during development and in adult physiology. Different mechanisms of active DNA demethylation have been established. For example, Growth Arrest and DNA Damage 45-(GADD45) and Ten-Eleven-Translocation (TET) proteins act in active DNA demethylation but their functional relationship is unresolved. Here we show that GADD45a physically interacts--and functionally cooperates with TET1 in methylcytosine (mC) processing. In reporter demethylation GADD45a requires endogenous TET1 and conversely TET1 requires GADD45a. On GADD45a target genes TET1 hyperinduces 5-hydroxymethylcytosine (hmC) in the presence of GADD45a, while 5-formyl-(fC) and 5-carboxylcytosine (caC) are reduced. Likewise, in global analysis GADD45a positively regulates TET1 mediated mC oxidation and enhances fC/caC removal. Our data suggest a dual function of GADD45a in oxidative DNA demethylation, to promote directly or indirectly TET1 activity and to enhance subsequent fC/caC removal.

Keywords: DNA demethylation; Gadd45; LC–MS/MS; TET; hmC.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • 5-Methylcytosine / metabolism
  • Cell Cycle Proteins / genetics
  • Cell Cycle Proteins / metabolism*
  • Cytosine / analogs & derivatives*
  • Cytosine / metabolism
  • DNA Methylation* / genetics
  • DNA-Binding Proteins / genetics
  • DNA-Binding Proteins / metabolism*
  • Gene Knockdown Techniques
  • HEK293 Cells
  • Humans
  • Immunoprecipitation
  • Mixed Function Oxygenases
  • Nuclear Proteins / genetics
  • Nuclear Proteins / metabolism*
  • Oxidation-Reduction
  • Protein Binding
  • Proto-Oncogene Proteins / genetics
  • Proto-Oncogene Proteins / metabolism*

Substances

  • 5-carboxylcytosine
  • 5-formylcytosine
  • Cell Cycle Proteins
  • DNA-Binding Proteins
  • GADD45A protein, human
  • Nuclear Proteins
  • Proto-Oncogene Proteins
  • 5-hydroxymethylcytosine
  • 5-Methylcytosine
  • Cytosine
  • Mixed Function Oxygenases
  • TET1 protein, human