m6Am-seq reveals the dynamic m6Am methylation in the human transcriptome

Abstract

Abstract N 6 ,2′- O -dimethyladenosine (m 6 Am), a terminal modification adjacent to the mRNA cap, is a newly discovered reversible RNA modification. Yet, a specific and sensitive tool to directly map transcriptome-wide m 6 Am is lacking. Here, we report m 6 Am-seq, based on selective in vitro demethylation and RNA immunoprecipitation. m 6 Am-seq directly distinguishes m 6 Am and 5′-UTR N 6 -methyladenosine (m 6 A) and enables the identification of m 6 Am at single-base resolution and 5′-UTR m 6 A in the human transcriptome. Using m 6 Am-seq, we also find that m 6 Am and 5′-UTR m 6 A respond dynamically to stimuli, and identify key functional methylation sites that may facilitate cellular stress response. Collectively, m 6 Am-seq reveals the high-confidence m 6 Am and 5′-UTR m 6 A methylome and provides a robust tool for functional studies of the two epitranscriptomic marks.