OAS1 enzyme is a member of the 2’，5’-oligoadenylate synthetase family. OAS1 is induced by interferons and uses adenosine triphosphate in 2’-specific nucleotidyl transfer reactions to synthesize 2’，5’-oligoadenylates（2-5As). These molecules in turn activate latent RNase L resulting in viral RNA degradation and the inhibition of viral replication.
OAS1 may have a role in mediating resistance to virus infection， control of cell growth， differentiation， and apoptosis. OAS1 binds double-stranded RNA and polymerizes ATP into PPP（A2’P5’A)N oligomers， which activate the latent RNase L that， once activated， cleaves single-stranded RNAs.
OAS1 gene mutations are been linked to host susceptibility to viral infection.
OSA1 gene polymorphisms are linked to the outcome of hepatitis C virus infection. Furthermore， OAS1 gene polymorphisms are linked to the susceptibility to severe acute respiratory syndrome.
