Detection and functions of viral RNA modifications: perspectives in biology and medicine.

Viral RNAs (either derived from DNA viruses and genomic/mRNAs of RNA viruses) produced and replicated in eukaryotic cells are exposed to the activity of host cell RNA modification machinery. Moreover, some complex viruses encode their own RNA modification enzymes, generally cap-related m7G-and 2'-O-methyltransferases whose expression allows specific modification of viral transcripts and modulation of viral RNA recognition by host restriction systems. Here we review current achievements in the detection of viral RNA modifications by liquid chromatography coupled to mass spectrometry (LC-MS) and deep sequencing-based approaches. The presence, origin and characterized functions of RNA modifications in viral RNAs are discussed.