oligoadenylate

Oligoadenylates are short polymers of adenosine nucleotides linked by 2',5'-phosphodiester bonds. In vertebrates, they are produced in response to viral double-stranded RNA by the interferon-induced 2'-5'-oligoadenylate synthetase (OAS) enzyme family.

OAS uses ATP to synthesize 2'-5'-oligoadenylates (2-5A) of two to six adenosine units, commonly with a 5'-triphosphate terminus. These molecules act as second messengers in antiviral signaling.

2-5A binds to RNase L, promoting its dimerization and activation. Activated RNase L cleaves single-stranded RNA, reducing viral replication and altering host gene expression, which can contribute to apoptosis under cellular stress.

In research and medicine, the OAS–RNase L pathway is studied as part of innate immunity and as a potential target for antiviral therapies. Synthetic 2-5A analogs are used to study RNase L activation and RNA degradation in cells.