title: Recombinant Marburg Viruses as Tool for the Characterization of Emerging Strains and the Analysis of Crucial Mechanisms during Viral Replication
title: Rekombinante Marburg-Viren als Werkzeug für die Charakterisierung neu auftretender Stämme und die Analyse entscheidender Mechanismen während der Virusreplikation
titleType: AlternativeTitle
Creators: name: von Creytz, Isabel
Publisher: name: Philipps-Universität Marburg
Year: 2024
Subjects: Marburg Virus
PP2A-B56
reverse genetics
Marburg virus
Virology
replication cycle
Medical sciences Medicine
Medizin
Replikationszyklus
Virologie
reverse Genetik

description: Marburg virus (MARV) belongs to the Filoviridae family and has lethality rates of up to 90%. Until recently, MARV usually occurred in Central Africa, but in 2021 the first case was documented in West Africa (Guinea). The continued spread of MARV (Ghana 2022, Equatorial Guinea and Tanzania 2023) highlights the relevance of characterizing newly emerging MARV and the importance of a comprehensive understanding of the viral replication cycle to identify potential antiviral targets. Reverse genetics systems are valuable tools to study individual steps of the replication cycle in detail and to confirm their effect with recombinant (rec) viruses.
In this context, during the first project the first West African MARV Guinea was generated using reverse genetics. Since the cloning protocols for full-length plasmids established in our laboratory were inefficient, these were optimized to be able to react more quickly in the event of new outbreak events (MS 3). Subsequently, the replication of recMARV Guinea was characterized in comparison to the well-known strains MARV Musoke and Leiden. It was demonstrated that recMARV Guinea replicated in human, monkey and fruit bat cells as efficiently as both strains MARV Musoke and Leiden. In addition, it was shown that the nucleoside analog remdesivir efficiently inhibited replication of the new recMARV Guinea in cell culture experiments.
In the second project, the role of the cellular protein phosphatase 2A-B56 (PP2A-B56) in the MARV replication cycle was investigated using different reverse genetic systems in order to characterize it as a potential antiviral target. It was confirmed that PP2A-B56 binds to the nucleoprotein (NP) via a specific interaction motif. This enabled the dephosphorylation of the viral transcription factor VP30, which is also bound to NP, thereby enhancing viral transcription. Inhibition of the interaction between NP and PP2A-B56 caused hyperphosphorylation of VP30 and reduced transcription. In addition, the NP - PP2A-B56 interaction was essential for the generation of recMARV. Finally, it was confirmed that a PP2A inhibitor significantly reduced replication in MARV infection studies. Accordingly, PP2A-B56 was confirmed to play an essential role in MARV transcription, as already demonstrated for the closely related Ebola virus, and was thereby identified as a potential pan-filoviral target.
These findings underline the potential of reverse genetics systems as a tool for the characterization of newly emerging MARV strains and for the analysis of mechanisms crucial for viral replication.