RNASEL and viral infectious disease: As expected, although binding dsRNA, dOASL-3K* together with the other two avian OASL mutants (dOASL-3D* and oOASL-3D*) lacked 2–5A activities and did not activate RNase L to degrade rRNA, failing to prevent virus infection in DF1 and DF1OASL−/− cells (Figures 4D,E; Figures S5 and S6 in Supplementary Material).