As obligate intracellular parasites, viruses are dependent on their hosts for replication. This poses a unique challenge: how can the virus usurp cellular resources whilst avoiding detection by immune surveillance complexes? For viruses with positive sense RNA genomes (+ssRNA), genome replication is coupled to the remodelling of host membranes, yielding organelles that camouflage their RNA within the cell. All such organelles require a point of exchange with the cytosol, allowing for entry of cellular metabolites and exit of the nascently synthesized genome for translation and packaging into new virions. For several viruses including the alphavirus superfamily and coronaviruses, macro pores have been identified within the organelle membrane that may serve as a molecular gates.
This project proposed to structurally characterize these viral pores at high resolution with cryo electron microscopy. Pore complexes were studied following extraction with single particle methods, and a method to purify replication organelles for ex situ analysis of pores in their native membranes was also developed. Characterization of the pores will allow us to understand how they are integrated into viral replication, providing new avenues for therapeutics.