Exploring the Life Cycle of Hepatitis E Virus

Background: Hepatitis E virus (HEV) is one of the most common causes of acute hepatitis and jaundice in the world. HEV genotypes 1 and 2 cause primarily waterborne outbreaks in resource-limited settings while genotypes 3 and 4 have emerged as porcine zoonosis in middle- and high-income areas including Switzerland. HEV is a positive-strand RNA virus encoding three open reading frames (ORFs). Key aspects of its life cycle remain unexplored.Specific aims: Two specific aims shall be pursued within the framework of this grant proposal.1.In the first aim, we shall characterize the HEV replication complex and further investigate host factors required for viral RNA replication.2.In the second aim, we shall gain insight into host factors interacting with the ORF2 protein, representing the viral capsid, and thereby deepen our understanding of its functions and the mechanisms of virion assembly.Experimental design and methods: The experiments proposed in this grant application build on the tools and the expertise that we have developed in the previous funding period. They involve molecular, biochemical and cell biological as well as virological techniques, including the replicon and infectious cell culture systems, advanced imaging and proteomics. These experimental techniques shall be complemented on a collaborative basis by electron microscopy.Expected value of the proposed project: The proposed project should yield new insights into the functional architecture of the HEV replication complex as well as the host factors involved in different steps of the viral life cycle, including RNA replication and virion assembly. It is expected to advance our understanding of the molecular virology of hepatitis E and is likely to yield results of broad biological significance.