# Structure and Assembly of Viruses

> **NIH NIH R01** · BOSTON CHILDREN'S HOSPITAL · 2021 · $420,375

## Abstract

Summary
The structure of a virus particle must conform to the mechanism by which it enters and infects a cell. We seek
to relate structures of virus particles and viral surface proteins to mechanisms of the steps in cell attachment,
uptake and penetration that initiate a productive infection. The proposed experiments take advantage of recent
advances in electron cryomicroscopy (cryo-EM) and live-cell imaging to define these mechanisms for both non-
enveloped and enveloped viruses, taking rotaviruses and flaviviruses (West Nile and dengue viruses, in
particular) as specific examples. Previous live-cell imaging studies defined the cellular entry pathway for
rhesus rotavirus (RRV). We can now relate structures we have determined for distinct conformations of the
spike-like viral protein 4 (VP4), which mediates cell entry, to stages of plasma-membrane remodeling in the
entry pathway. We will extend on-going analyses by cryo-EM of VP4 conformations at the membrane interface,
both on cells and in an in vitro-reconstituted system for early steps, to determine how RRV deforms and then
disrupts a membrane bilayer. A mechanism for RRV membrane perforation, suggested by preliminary data,
may help unify observations made with several other RNA viruses. Proposed experiments will connect high-
resolution structures with direct analyses (by electron cryotomography and potentially by high-resolution
template matching) of VP4 conformations during cell entry and with sequences of events in time (by lattice-
light-sheet microscopy). For the flavivirus fusion protein (the "E protein"), completing a structure for the
postfusion conformation of the intact protein will enable design of experiments to trap fusion intermediates and
thus to define the fusion mechanism more completely than hitherto possible. The intended outcomes of the
studies, for both rotaviruses and flaviviruses, are structurally and mechanistically accurate "molecular movies"
of viral entry.

## Key facts

- **NIH application ID:** 10064130
- **Project number:** 5R01CA013202-48
- **Recipient organization:** BOSTON CHILDREN'S HOSPITAL
- **Principal Investigator:** STEPHEN COPLAN HARRISON
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2021
- **Award amount:** $420,375
- **Award type:** 5
- **Project period:** 1975-06-01 → 2024-11-30

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10064130

## Citation

> US National Institutes of Health, RePORTER application 10064130, Structure and Assembly of Viruses (5R01CA013202-48). Retrieved via AI Analytics 2026-05-24 from https://api.ai-analytics.org/grant/nih/10064130. Licensed CC0.

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