Amino acids 81 and 82 of the mouse RNase L are also necessary for interaction with and inhibition by L*.

A. Segments of decreasing size were swapped between rat and mouse RNase L and the resulting chimeric RNase L were tested for inhibition by and interaction with L*_DA (mouse virus) and L*_RTV-1 (rat virus)_. Schematic rat/mouse chimeric RNase L are represented as in Fig 2. The right columns indicate whether L*_DA and L*_RTV-1 interact with and inhibit the chimeric enzymes. B-C. Immunoblots (B) show Flag and HA detection after immunoprecipitation of HA-L* (IP:HA) and in cell lysates (Input). Graphs (C) show the mean and SD of the amount of co-immunoprecipitated RNase L chimera relative to that of WT RNase L of the corresponding species (n = 3). *: p<0.05 in a two-way ANOVA followed by Dunnett’s test for multiple comparison. D. Analysis of RNase L-mediated RNA degradation in HeLa-M cells overexpressing indicated Flag-RNase L and L*_DA or L*_RTV-1. RNA samples were extracted 7 hours after polyI:C transfection. Arrowheads point to rRNA cleavage products. Reproducible results were obtained in 2 independent experiments.