Fig mosaic virus mRNAs show generation by cap-snatching

Fig mosaic virus (FMV), a member of the newly described genus Emaravirus, has four negative-sense single-stranded genomic RNAs, and each codes for a single protein in the viral complementary RNA (vcRNA). In this study we show that FMV mRNAs for genome segments 2 and 3 contain short (12–18 nucleotides) heterogeneous nucleotide leader sequences at their 5′ termini. Furthermore, by using the high affinity cap binding protein eIF4EK119A, we also determined that a 5′ cap is present on a population of the FMV positive-sense RNAs, presumably as a result of cap-snatching. Northern hybridization results showed that the 5′ capped RNA3 segments are slightly smaller than the homologous vcRNA3 and are not polyadenylated. These data suggest that FMV generates 5′ capped mRNAs via cap-snatching, similar to strategies used by other negative-sense multipartite ssRNA viruses.

► We determine heterogeneous non viral leader sequences at the 5′ termini of Fig mosaic virus (FMV).
► We determine presence of 5′ cap on the positive sense RNAs of FMV.
► We indicate FMV (mRNA) transcription initiation by 5′ cap snatching mechanism.
► We show smaller transcripts (mRNA) for RNA3 compared to vcRNA suggesting internal termination of transcription.