OAS1 and viral infectious disease: Induction of OAS proteins by IFN and viral replication leads to synthesis of 2’5’ oligoadenylates which activate RNase L. OASs (OAS1, OAS2, OAS3) synthesize 2’-5’ oligoadenylates and activate RNase L leading to degradation of viral and cellular RNAs, thereby restricting viral infections [38].