A Reader-Based Assay for m 6 A Writers and Erasers.

We have developed a homogeneous time resolved fluorescence (HTRF)-based enzyme assay to measure the catalytic activity of N-6-methyladenosine (m(6)A) methyltransferases and demethylases. The assay detects m(6)A modifications using the natural m(6)A-binding proteins (m(6)A readers). The reaction product or substrate m(6)A-containing RNA and the m(6)A reader protein are fluorescently labeled such that their proximity during binding initiates Forster resonance energy transfer (FRET). We show that our HTRF assay can be used for highthroughput screening, which will facilitate the discovery of smallmolecule modulators of m(6)A (de)methylases.