# Structural Mechanisms of Ebola Virus RNA Synthesis

> **NIH NIH P01** · WASHINGTON UNIVERSITY · 2020 · $773,062

## Abstract

The recent Ebola virus (EBOV) outbreak in Western Africa, which introduced the virus to non-African nations 
including the United States, highlights the imminent threat to global health posed by filoviruses and the urgent 
need for basic and translational efforts. A critical step in the viral lifecycle of filoviruses is the replication of the 
non-segmented, negative strand RNA genome by the viral RNA dependent RNA polymerase (RDRP) complex. 
The EBOV RDRP complex is composed of the large protein (L), nucleoprotein (NP), viral protein 35 (VP35) and 
viral protein 30 (VP30) and is essential for transcription of viral mRNA and replication of antigenomic and 
genomic RNA. During RNA synthesis, components of the RDRP complex undergo multiple structural 
rearrangements to make the NP-associated RNA template accessible to the L polymerase while protecting the 
NP-RNA template from cellular nucleases. Despite the importance of the EBOV RDRP complex to pathogenesis 
and the potential as therapeutic targets, insights into RDRP complex assembly and its regulatory interactions 
with host or viral proteins are lacking. We will address these longstanding mechanistic questions in this PPG. 
Project 2 will use biochemical and hybrid structural methods that will combine results from NMR, X-ray 
crystallography, small angle X-ray scattering (SAXS) and cryo-electron microscopy (cryoEM) in order to define 
the molecular mechanism of the EBOV RDRP complex assembly and function, and to define its regulatory 
mechanisms and structural dynamics. Our strong preliminary results support a working model where 
conformational remodeling of the RDRP complex is controlled by cis- and trans-acting factors. We have 
assembled a highly productive and collaborative team of investigators with complementary expertise to perform 
the following Aims: 1. Define the molecular mechanism by which EBOV VP35 facilitates delivery of NP in the 
RNA-free form. 2. Elucidate the internal dynamics of the NP protein and define the role of different NP 
conformations in viral RNA synthesis. 3. Determine the molecular architecture of the EBOV RDRP complex by 
hybrid structural methods. 4. Determine the structural basis for cis-acting RNA elements identified in Project 1 
and novel host factors from Project 3/Core B that regulate EBOV RDRP complex. Completion of these studies 
will address longstanding and critical mechanistic questions in EBOV biology that are also central to a better 
understanding of non-segmented negative sense RNA viruses (NNSVs). These insights are also expected to 
yield new opportunities for antiviral development.

## Key facts

- **NIH application ID:** 9955176
- **Project number:** 5P01AI120943-05
- **Recipient organization:** WASHINGTON UNIVERSITY
- **Principal Investigator:** Gaya K. Amarasinghe
- **Activity code:** P01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2020
- **Award amount:** $773,062
- **Award type:** 5
- **Project period:** 2016-07-07 → 2023-06-30

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/9955176

## Citation

> US National Institutes of Health, RePORTER application 9955176, Structural Mechanisms of Ebola Virus RNA Synthesis (5P01AI120943-05). Retrieved via AI Analytics 2026-05-24 from https://api.ai-analytics.org/grant/nih/9955176. Licensed CC0.

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