Figure 2: Assay of oosporein-mediated inhibition of cap-snatching activity. [³²P]Cap 1-GACU₃₂-biot (50 fmol) was incubated with increasing amounts of oosporein and influenza virus A virions (1 μg). Cap-snatching activity is expressed as the ratio of the amount of cleaved RNA to the amount of total capped RNA. Typical results of three independent experiments are shown.