Rift Valley fever virus NSS gene expression correlates with a defect in nuclear mRNA export

- Rift Valley fever virus (RVFV) infection alters the localization of host mRNA.
- mRNA accumulates in the nuclei of RVFV-infected but not mock-infected cells.
- NSS is likely responsible for mRNA relocalization to the nucleus.

We investigated the localization of host mRNA during Rift Valley fever virus (RVFV) infection. Fluorescence in situ hybridization revealed that infection with RVFV altered the localization of host mRNA. mRNA accumulated in the nuclei of RVFV-infected but not mock-infected cells. Further, overexpression of the NSS gene, but not the N, GN or NSM genes correlated with mRNA nuclear accumulation. Nuclear accumulation of host mRNA was not observed in cells infected with a strain of RVFV lacking the gene encoding NSS, confirming that expression of NSS is likely responsible for this phenomenon.