Cross virus comparison of coronavirus proteins involved in replication organelle formation

Session

Poster Session One

Authors

Conor Haydon (1), Nicole Doyle (1), Joanna Wells (1), Jennifer Simpson (1), Phillipa Hawes (1), Helena Maier (1)

Affiliations

1. The Pirbright Institute

Keywords

Coronavirus, replication organelle, CLEM, electron tomography

Abstract text

Like all positive sense RNA viruses, coronaviruses (CoVs) induce the rearrangement of cellular membranes during infection to form the replication organelle (RO). The RO provides a platform for assembly of the viral RNA synthesis machinery and a membrane protected environment for nascent viral RNA. We previously characterised that the RO is comprised of double membrane vesicles (DMVs) and double membrane spherules (DMSs) and these structures make up the conserved RO for all CoVs. Due to its conserved nature and central role in virus replication, the RO provides an attractive target for antiviral strategies that may be effective against multiple CoVs. Gaining a more complete understanding of RO formation and function is essential to inform design of antiviral strategies. Others have demonstrated that co-expression of Betacoronavirus membrane-spanning non-structural proteins nsp3 and nsp4 is sufficient for DMV formation. Interestingly however, our earlier work with the Gammacoronavirus infectious bronchitis virus indicated that co-expression of these two proteins resulted in zippering of ER membranes but was not sufficient for DMV formation. To develop on from these observations and gain and a more detailed understanding of potential variations in how CoVs from different genera achieve RO formation, we are using plasmid and replicon-based expression systems combined with correlative light electron microscopy and electron tomography to identify which viral proteins are responsible for RO formation.