[F31] Investigating how membrane localization and oligomerization drive OAS1 p46 antiviral activity

Description

Project Summary/Abstract This project investigates the antiviral function of the innate immune protein OAS1 p46, a splice isoform of 2'-5'-oligoadenylate synthetase 1 (OAS1). OAS1 p46, is a double-stranded (ds)RNA sensor that restricts +ssRNA virus replication by synthesizing 2-5A for activation of ribonuclease L (RNase L), an enzyme that degrades viral and cellular single-stranded RNA. OAS1 p46 displays enhanced antiviral activity compared to the cytosolic isoform OAS1 p42, due to three unique features: CaaX-mediated membrane localization, an extended C-terminus, and the capacity to form oligomers. However, the mechanisms through which localization and oligomerization enhance antiviral function remain unknown. The research aims to define how spatial localization and oligomerization of OAS1 p46 regulate antiviral activity against +ssRNA viruses. Aim 1 will determine whether OAS1 p46 activates RNase L locally at sites of viral RNA synthesis on viral replication organelles (VROs). Transmission electron microscopy and live-cell imaging using a BiFC-based RNase L activity reporter will be used to determine whether OAS1 p46 localizes near viral replication complexes on viral replication organelles (VROs) and whether it activates RNase L locally to sites of viral RNA synthesis. Aim 2 investigates how OAS1 p46 forms oligomers and define their role in antiviral activity. In vitro and in cell 2-5A synthesis/reporter assays and irCLIP will be used to determine whether OAS oligomers enhance dsRNA binding avidity and 2-5A synthesis. This research will provide new insights into how spatial compartmentalization and structural assembly of immune effectors enhance antiviral signaling. Understanding these mechanisms has broad relevance to the development of spatially targeted immunotherapies, host-directed antiviral strategies, and synthetic immune sensors. The proposed training integrates expertise in virology, innate immunity, RNA biology, and advanced microscopy within a highly collaborative environment at the University of Washington. This fellowship will support the candidate’s scientific development and contribute to the NIH mission of improving public health through fundamental research in immune defense. Istituzione: UNIVERSITY OF WASHINGTON PI: Skyler Lynn Niemeyer Progetto: 1F31AI200452-01

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Source: reporter.nih.gov