Dynamics and heterogeneity of early viral infection

Introduction

Viruses are simple replicative units built from two components: a nucleic acid and a small number of associated proteins. Upon entering a cell, viruses co-opt the host's machineries to copy their genetic material while shutting down the host's antiviral immune response. The success of viral infection differs dramatically from cell to cell through poorly understood mechanisms, resulting in heterogeneous propagation through tissues and ultimately, heterogeneous disease progression.

Challenges in Studying Viral Infection

Although viruses have been studied for decades, the earliest steps of cellular infection have remained hidden because only a few viral molecules are present at this stage, which presents formidable challenges for molecular analyses. Yet, these initial events are critical for achieving a successful infection; transcription, translation, and replication must be perfectly balanced to rapidly scale virus production before antiviral signaling pathways are activated.

New Imaging Technology

To overcome this barrier, we recently developed a first-in-kind imaging technology for simple positive-sense single-stranded RNA (+ssRNA) viruses that transforms our ability to visualize early viral infection processes.

Proposal Overview

In this proposal, we will expand our single-molecule toolbox to gain molecular insights into early viral infection of the more complex group of negative-sense RNA (-ssRNA) viruses. We will focus on the respiratory syncytial virus (RSV), a -ssRNA virus that can be deadly in infants and vulnerable adults and lacks effective treatments.

Research Objectives

Specifically, we will determine:

1. How viral transcription and replication are coordinated on single viral genomic RNA molecules to optimize early viral propagation.
2. What causes the early viral infection heterogeneity.
3. How heterogeneity in early viral infection impacts infection outcome.

Expected Outcomes

Using our novel approaches, we will gain a deep understanding of viral biology, which will eventually inform therapeutic interventions.