Genomic RNAs of segmented NSVs.
RNAs isolated from virus particles of LASV (A) and RVFV (B) were tested for their ability to activate the IFN-β promoter in dependency of RIG-I or MDA5 (left panels) or 5′ triphosphate groups (right panels). (C) IFN-β promoter activation by genomic RNAs of the bunyaviruses RVFV, HTNV, and CCHFV. Mean values and standard deviations from 3 independent experiments are shown. (D) Purified virion RNAs (5 µg) of RVFV, HTNV, and CCHFV were separated on denaturing formaldehyde agarose gels. The genome segments (L, large; M, middle; S, small) are labeled on the right, and asterisks indicate 28S and 18S rRNA bands. Contamination of virus preparations with ribosomal RNAs are often observed  but have no consequences for IFN induction. As a control RNA isolated from ultracentrifuged supernatants of uninfected cells is shown (mock).