Hepatitis E Virus RNA‐Dependent RNA Polymerase is Involved in RNA Replication and Infectious Particle Production

Noémie Oechslin (1) , Nathalie da Silva (1) , Dagmara Szkolnicka (1) , François‐xavier Cantrelle (2, 3) , Xavier Hanoulle (2, 3) , Darius Moradpour (1) , Jérôme Gouttenoire (1)

1 UNIL - Université de Lausanne = University of Lausanne
2 ERL 9002 - BSI - Biologie Structurale Intégrative
3 RID-AGE - Facteurs de Risque et Déterminants Moléculaires des Maladies liées au Vieillissement - U 1167

Background and Aims: Hepatitis E virus (HEV) is one of the most common causes of acute hepatitis worldwide. Its positive-strand RNA genome encodes three open reading frames (ORF). ORF1 is translated into a large protein composed of multiple domains and known as the viral replicase. The RNA-dependent RNA polymerase (RdRp) domain is responsible for the synthesis of viral RNA. Approach and Results: Here, we identified a highly conserved α-helix located in the RdRp thumb subdomain. Nuclear magnetic resonance demonstrated an amphipathic α-helix extending from amino acids 1628 to 1644 of the ORF1 protein. Functional analyses revealed a dual role of this helix in HEV RNA replication and virus production, including assembly and release. Mutations on the hydrophobic side of the amphipathic α-helix impaired RNA replication and resulted in the selection of a second-site compensatory change in the RdRp palm subdomain. Other mutations enhanced RNA replication but impaired virus assembly and/or release. Conclusions: Structure-function analyses identified a conserved amphipathic α-helix in the thumb subdomain of the HEV RdRp with a dual role in viral RNA replication and infectious particle production. This study provides structural insights into a key segment of the ORF1 protein and describes the successful use of reverse genetics in HEV, revealing functional interactions between the RdRp thumb and palm subdomains. On a broader scale, it demonstrates that the HEV replicase, similar to those of other positive-strand RNA viruses, is also involved in virus production

Mots clés: HEV; particle production; RdRp; reverse genetics; thumb subdomain

Domaines: Virologie; Biologie structurale [q-bio.BM]; Maladies infectieuses; Hépatologie et Gastroentérologie

Noémie Oechslin, Nathalie da Silva, Dagmara Szkolnicka, François‐xavier Cantrelle, Xavier Hanoulle, et al.. Hepatitis E Virus RNA‐Dependent RNA Polymerase is Involved in RNA Replication and Infectious Particle Production. Hepatology, 2021, ⟨10.1002/hep.32100⟩. ⟨hal-03326608⟩