AlkAniline-Seq: A Highly Sensitive and Specific Method for Simultaneous Mapping of 7-Methyl-guanosine (mG) and 3-Methyl-cytosine (mC) in RNAs by High-Throughput Sequencing

Epitranscriptomics is an emerging field where the development of high-throughput analytical technologies is essential to profile the dynamics of RNA modifications under different conditions. Despite important advances during the last 10 years, the number of RNA modifications detectable by next-generation sequencing is restricted to a very limited subset. Here, we describe a highly efficient and fast method called AlkAniline-Seq to map simultaneously two different RNA modifications: 7-methyl-guanosine (mG) and 3-methyl-cytosine (mC) in RNA. Our protocol is based on three subsequent chemical/enzymatic steps allowing the enrichment of RNA fragments ending at position n + 1 to the modified nucleotide, without any prior RNA selection. Therefore, AlkAniline-Seq demonstrates an outstanding sensitivity and specificity for these two RNA modifications. We have validated AlkAniline-Seq using bacterial, yeast, and human total RNA, and here we present, as an example, a synthetic view of the complete profiling of these RNA modifications in S. cerevisiae tRNAs.