[Septin9 promotes viral replication by interacting with Ebola virus VP35 to regulate inclusion body formation]

The Ebola virus (EBOV), a member of the Filoviridae family, is a highly pathogenic agent responsible for severe hemorrhagic fever in humans. Understanding the molecular mechanisms governing its replication is critical for developing effective antiviral strategies. VP35-TurboID immunosuppression coupled with quantitative mass spectrometry identified Septin9, the host GTP-binding protein which played a role in cytoskeletal regulation, as a novel interactor of VP35. Western blotting and Far-Western blotting confirmed the direct interaction and demonstrated that the C-terminal region of VP35 was the critical binding domain. Functionally, EBOV replication as well as the formation of viral inclusion bodies (VIBs) was demonstrated to be significantly suppressed by Septin9 knockdown and depletion, as shown by the EBOV minigenome (EBOV MG) and the transcription- and replication-competent virus-like particles (trVLPs) system. This study reveals that VP35 engages in a specific interaction with the GTP-binding protein Septin9, thereby impeding EBOV replication through the disruption of inclusion bodies. The overarching objective of this study is to significantly enhance our understanding about the pathogenic mechanism of EBOV and offer a robust theoretical foundation and solid empirical support for the formulation of innovative therapeutic strategies against EBOV.