While all three OASs (OAS1 to -3) produce 2-5A upon binding dsRNA in vitro or when overexpressed (21), we showed previously, using a series of cells with OAS gene knockouts (KOs), that only OAS3 was required for detectable activation of RNase L during infection of three human cell lines with diverse viruses (26). The gene discussed is RNASEL; the disease is infection.