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 [49] but have no consequences for IFN induction. As a control RNA isolated from ultracentrifuged supernatants of uninfected cells is shown (mock).