Regulation of Active DNA Demethylation through RAR-Mediated Recruitment of a TET/TDG Complex

Publication date: 23 May 2017
Source:Cell Reports, Volume 19, Issue 8
Author(s): Haider M. Hassan, Bart Kolendowski, Majdina Isovic, Kerstin Bose, Helen J. Dranse, Arthur V. Sampaio, T. Michael Underhill, Joseph Torchia
Retinoic acid (RA) plays important roles in development, growth, and homeostasis through regulation of the nuclear receptors for RA (RARs). Herein, we identify Hypermethylated in Cancer 1 (Hic1) as an RA-inducible gene. HIC1 encodes a tumor suppressor, which is often silenced by promoter hypermethylation in cancer. Treatment of cells with an RAR agonist causes a rapid recruitment of an RAR/RXR complex consisting of TDG, the lysine acetyltransferase CBP, and TET 1/2 to the Hic1 promoter. Complex binding coincides with a transient accumulation of 5fC/5caC and concomitant upregulation of Hic1 expression, both of which are TDG dependent. Furthermore, conditional deletion of Tdg in vivo is associated with Hic1 silencing and DNA hypermethylation of the Hic1 promoter. These findings suggest that the catalytic and scaffolding activities of TDG are essential for RA-dependent gene expression and provide important insights into the mechanisms underlying targeting of TET-TDG complexes.

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Teaser

Hassan et al. report that DNA methylation and expression of Hypermethylated in Cancer 1 (Hic1) are regulated by the retinoic acid receptor (RAR) in a TDG dependent manner. Failure to recruit TDG and TETs may contribute to aberrant silencing of HIC1 in cancer.


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