OAS1 and viral infectious disease: Similar to IFITM, 2′–5′-oligoadenylate synthetases (OAS1, OAS2, OAS3) are induced by type I IFN interferons and in the presence of viral dsRNA OAS catalyze oligomerisation of ATP to form 2′–5′-linked adenosine oligomers (2-5A), which would involve in the activation of RNase L degradative pathway that would cleave the viral RNA and ultimately control viral infection (Kristiansen et al., 2010; Leisching et al., 2019).