RNA modifications go viral

Viral life cycles are often coordinated by precise mechanisms that act on their RNA. For example, the microRNA miR-122 interacts with the viral RNA genome of hepatitis C virus (HCV) and is required for HCV replication [1]. In the past year, several groups have reported a new RNA regulatory control to viral infection—the posttranscriptional RNA modification N6methyladenosine (mA). This reversible RNA modification is the most prevalent internal modification of the more than 60 known chemical modifications in eukaryotic RNA. The deposition of mA on RNA is controlled by cellular mA machinery comprising methyltransferase and demethylase enzymes, as well as mA-specific binding proteins (recently reviewed in [2]; Fig 1). By affecting mRNA and noncoding RNA structure, localization, and function, mA plays an important role in many fundamental biological processes [2]. A role for mA in viral infection has been hypothesized since the 1970s, when mA was found on RNA of several viruses [3–7]. Recently, advances in sequencing-based strategies used to profile mA have expanded the known repertoire of viruses with mA in their RNA to include human immunodeficiency virus 1 (HIV-1) and RNA viruses in the family Flaviviridae,