Dynamic Readers for 5-(Hydroxy)Methylcytosine and Its Oxidized Derivatives
Cornelia G. Spruijt, Felix Gnerlich, Arne H. Smits, Toni Pfaffeneder, Pascal W.T.C. Jansen, Christina Bauer, Martin Münzel, Mirko Wagner, Markus Müller, Fariha Khan, H. Christian Eberl, Anneloes Mensinga, Arie B. Brinkman, Konstantin Lephikov, Udo Müller, Jörn Walter, Rolf Boelens, Hugo van Ingen, Heinrich Leonhardt, Thomas Carell, Michiel Vermeulen
- Identification of readers for 5-(hydroxy)methylcytosine in (differentiated) mESCs
- mC and hmC readers are highly dynamic during development and show limited overlap
- Oxidized derivatives of mC recruit DNA repair proteins in mESCs
- Uhrf2 stimulates the activity of the Tet1 enzyme
Tet proteins oxidize 5-methylcytosine (mC) to generate 5-hydroxymethyl (hmC), 5-formyl (fC), and 5-carboxylcytosine (caC). The exact function of these oxidative cytosine bases remains elusive. We applied quantitative mass-spectrometry-based proteomics to identify readers for mC and hmC in mouse embryonic stem cells (mESC), neuronal progenitor cells (NPC), and adult mouse brain tissue. Readers for these modifications are only partially overlapping, and some readers, such as Rfx proteins, display strong specificity. Interactions are dynamic during differentiation, as for example evidenced by the mESC-specific binding of Klf4 to mC and the NPC-specific binding of Uhrf2 to hmC, suggesting specific biological roles for mC and hmC. Oxidized derivatives of mC recruit distinct transcription regulators as well as a large number of DNA repair proteins in mouse ES cells, implicating the DNA damage response as a major player in active DNA demethylation.