Since this was our first observation of RNase L activity during alphacoronavirus infection, we assessed the percentage of infected cells that activated RNase L by IF assays for dsRNA (infection marker) and poly[a]-binding protein-1 (PABPC1), which translocates from the cytosol to the nucleus upon activation of RNase L-mediated mRNA decay (51, –, 53). The gene discussed is PABPC1; the disease is infection.