RNASEL and viral infectious disease: In most vertebrates, viruses induce an RNA degradation process that is regulated through the action of the ubiquitous cellular endoribonuclease RNase L. Type I IFN produced during viral infections transcriptionally induces OAS proteins that are activated by binding dsRNA to produce a unique 2′,5′-oligoadenylate, 2-5A [px5′A(2′p5′A)n; x = 1 to 3; n ≥ 2], produced from cellular ATP.