# Picornavirus Genome Replication

> **NIH NIH R37** · UNIV OF NORTH CAROLINA CHAPEL HILL · 2021 · $449,205

## Abstract

Project Abstract
This is an application for renewal of a grant to study picornavirus genome replication. Studies of poliovirus
(PV) continue to establish paradigms for the molecular and cellular biology of all positive-strand RNA viruses
capable of causing morbidity and/or mortality in humans. PV replicates its genome in association with
membranes. In fact, the virus creates its own genome-replication organelle (RO) with a unique lipid
composition, including an abundance of the phosphoinositide (PIP), phosphatidylinositol-4-phosphate (PI4P).
During the past five years, many laboratories have been in search of the mechanism by which PI4P
biosynthesis is induced by various picornaviruses, including PV. In general, these studies tested the
hypothesis that a single viral protein hijacks a single cellular PI4 kinase (PI4K), leading to kinase relocalization
and synthesis of PI4P. Because of the long-established connection between the enteroviral 3A(B) protein and
the guanine nucleotide exchange factor, GBF1, most of the early studies focused on 3A(B) and concluded that
this viral protein is responsible for hijacking a PI4K, often by an indirect mechanism. However, this once-held
consensus opinion has now returned to uncertainty. Many years ago, our laboratory obtained genetic
evidence of a possible role of 3CD in the biogenesis of PV RO. During the previous funding period, we made a
definitive connection between 3CD and RO biogenesis by showing that 3CD is both necessary and sufficient
for induction of PI4P biosynthesis in cells. We demonstrated that the normal cellular GBF1-Arf1-PI4K axis is
employed. We identified two derivatives of 3CD with amino acid substitutions in the 3C domain (3CmD) or 3D
domain (3CDm) that are defective for induction of PI4P biosynthesis at discrete steps in this pathway. In both
instances, the derivatives exhibit perturbations to PIP-binding activity of 3CD. In addition to PI4P, 3CD also
induces PI(4,5)P2 (PIP2) biosynthesis in cells. PIP2 induction does not arise from the 3CD-dependent
increase in PI4P but appears to be a distinct process based on the observation that both 3CmD and 3CDm
proteins remain competent for PIP2 induction. PV 3CD is a PIP-binding protein and a regulator of multiple PIP
biosynthetic pathways. Our proposed studies aim to address how and why. During the next funding period,
we will pursue the following specific aims: (1) Define the structure-function relationships of the PIP-binding
domains of 3C and 3D alone and in the context of 3CD; (2) Elucidate the mechanism of induction of PI4P
biosynthesis by 3CD alone and in the context of infection; and (3) Elucidate the mechanism of induction of
PIP2 biosynthesis by 3CD alone and in the context of infection.

## Key facts

- **NIH application ID:** 10119227
- **Project number:** 5R37AI053531-18
- **Recipient organization:** UNIV OF NORTH CAROLINA CHAPEL HILL
- **Principal Investigator:** CRAIG E. CAMERON
- **Activity code:** R37 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2021
- **Award amount:** $449,205
- **Award type:** 5
- **Project period:** 2019-09-20 → 2023-01-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10119227

## Citation

> US National Institutes of Health, RePORTER application 10119227, Picornavirus Genome Replication (5R37AI053531-18). Retrieved via AI Analytics 2026-05-23 from https://api.ai-analytics.org/grant/nih/10119227. Licensed CC0.

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