m6A in 5' untranslated regions promotes cap-independent translation of mRNA

N6-methyladenosine (m6A) is a widespread internal RNA modification whose function is poorly understood. Here we report that m6A residues within the 5'UTR promote a novel form of cap-independent translation which is mediated through an interaction between m6A residues and the translation initiation factor, eIF3. We performed m6A profiling in cells subjected to heat shock stress and observed increased 5'UTR methylation after heat shock. For these studies, we used single-nucleotide resolution m6A mapping (miCLIP), which enables the detection of m6A residues separately from m6Am residues. Thus, the goal of these experiments was to identify m6A residues which are increased in the 5'UTR after heat shock stress. Overall design: Two replicates of eIF3a PAR-iCLIP in HEK293T cells. m6A profiling in HEK and HepG2 cells after heat shock.