OAS1 Gene - 2'-5'-Oligoadenylate Synthetase 1 | Function, Mutations & Disease

OAS1 (2'-5'-Oligoadenylate Synthetase 1) encodes a member of the 2-5A synthetase family, which is induced by interferons and catalyzes the synthesis of 2',5'-oligoadenylates (2-5A) from ATP. These 2-5A molecules activate latent RNase L, leading to viral RNA degradation and inhibition of viral replication. OAS1 plays a critical role in the innate immune response against RNA viruses, including influenza, hepatitis C, and coronaviruses. Multiple splice variants exist, producing isoforms with different subcellular localizations and activities.

Tissue Expression

Cell Line Expression

Hotspot Mutations

Mutation functional classification

• Interferon alpha/beta signaling (Reactome: R-HSA-909733)

• OAS antiviral response (Reactome: R-HSA-8983711)

• Innate immune system (Reactome: R-HSA-168249)

OAS1 is a 363-amino acid protein (canonical isoform) that belongs to the 2-5A synthetase family. It contains a nucleotidyltransferase domain and a double-stranded RNA binding domain. Upon binding dsRNA (viral replication intermediate), OAS1 polymerizes ATP into 2',5'-linked oligoadenylates (2-5A). These 2-5A molecules bind and activate RNase L, which degrades viral and cellular RNA, thereby limiting viral spread. OAS1 is induced by type I interferons and is localized primarily in the cytoplasm. Multiple isoforms (p46, p42, p40, p38) arise from alternative splicing, with the p46 isoform being the most active.