ABSTRACT: N6-methyladenosine (m6A) is the methylation of adenosine at position N6 and is notably one of the most abundant modifications found in mRNA of eukaryotes. Although it does not interrupt the coding functions of transcripts, it assists in regulating several RNA functions like splicing, stability, translocation and translation and is associated with disease development, cell proliferation, cell migration, cell invasion, autophagy, cell apoptosis, and drug resistance. In this study, we performed a colorimetric assay, ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS), and methylated RNA immunoprecipitation sequencing (MeRIP-seq) to assess the RNA N6-methyladenosine landscape of Echinococcus granulosus; a tapeworm species of the phylum Platyhelminthes that is responsible for a cosmopolitan zoonosis (cystic echinococcosis) of public health importance. While the levels of m6A modification were not significantly different between the life cycle stages, many important genes including notably enriched and expanded protein domains like Dyneins, Hsp70, and Cadherin thought to play important roles in adaptation to parasitism were m6A-modified. These genes were functionally enriched in biological processes like cell division, cell adhesion, microtubule-based movement, important pathways involved in parasitism (e.g. MAPK), and disease processes. Additionally, the m6A alterations were present in the first exon of modified genes, suggesting gene regulatory activities. Conclusively, m6A modification of the mRNA is present in Echinococcus, and is mediated by orthologues of known mammalian methyltransferases but possibly irreversible due to the absence of demethylases. The demonstration of differentially m6A-methylation in the different life cycle stages of Echinococcus suggests a role in the development and survival of the tapeworm. It also provides the groundwork for future studies in understanding the implication of RNA methylation in the treatment of echinococcoses.
