Rab11a mediates cell-cell spread and reassortment of influenza A virus genomes via tunneling nanotubes

Abstract

Influenza A virus [IAV] genomes comprise eight negative strand RNAs packaged into virions in the form of viral ribonucleoproteins [vRNPs]. Rab11a plays a crucial role in the transport of vRNPs from the nucleus to the plasma membrane via microtubules, allowing assembly and virusproduction. Here, we identify a novel function for Rab11a in the inter-cellular transport of IAV vRNPs using tunneling nanotubes [TNTs]as molecular highways. TNTs are F-Actin rich tubules that link the cytoplasm of nearby cells. In IAV-infected cells, Rab11a was visualized together with vRNPs in these actin-rich intercellular connections. To better examine viral spread via TNTs, we devised an infection system in which conventional, virion-mediated, spread was not possible. Namely, we generated HA-deficient reporter viruses which are unable to produce progeny virions but whose genomes can be replicated and trafficked. In this system, vRNP transfer to neighboring cells was observed and this transfer was found to be dependent on both actin and Rab11a. Generation of infectious virus via TNT transfer was confirmed using donor cells infected with HA-deficient virus and recipient cells stably expressing HA protein. Mixing donor cells infected with genetically distinct IAVs furthermore revealed the potential for Rab11a and TNTs to serve as a conduit for genome mixing and reassortment in IAV infections. These data therefore reveal a novel role for Rab11a in the IAV life cycle, which could have significant implications for within-host spread, genome reassortment and immune evasion.

Influenza A virus reassortment in mammals gives rise to genetically distinct within-host subpopulations

“…Although variation in the diversity generated through reassortment is apparent, visualization of viral antigen in infected tissues indicated that cellular co-infection is abundant at all sites examined. Cellular co-infection has previously been reported to be common in vivo 37 and is expected owing to the high potential for singular genomes to result in abortive infection 38 , 39 and the potential for direct cell-to-cell spread of viral genetic material 40 . Nevertheless, the juxtaposition of this result with a predominance of parental-type viruses in many samples is counter-intuitive.…”

Influenza A virus reassortment in mammals gives rise to genetically distinct within-host sub-populations

“…Although variation in the diversity generated through reassortment is apparent, visualization of viral antigen in infected tissues indicated that cellular co-infection is abundant at all sites examined. Cellular co-infection has previously been reported to be common in vivo 34 and is expected owing to the high potential for singular genomes to result in abortive infection 35,36 and the potential for direct cell-to-cell spread of viral genetic material 37 . Nevertheless, the juxtaposition of this result with a predominance of parental-type viruses in many samples is counter-intuitive.…”

Herpes Simplex Virus Type 1 Infection Induces the Formation of Tunneling Nanotubes

“…In 2008, it was found for the first time that a virus (HIV-1) can be transmitted through TNT [ 5 ]. Subsequent studies found that viruses such as orthomyxoviruses (e.g., influenza A virus, IAV) [ 6 ] and alphaherpesvirus (e.g., pseudorabies virus, PRV) [ 7 ] can spread through TNTs. The formation of TNT is a new mode of virus transmission, which facilitates the virus to spread to non-adjacent cells.…”