RAG1 and infection: Northern blot analysis showed that infection with either NoVΔB2 or NoVmB2 induced production of vsiRNAs in Stat1/2−/− adult mice at levels comparable to that in C57BL/6 mice (Fig. 6A), which accumulated markedly reduced levels of vsiRNAs compared to that in Rag1−/− mice (Fig. 3A).