Related Experiment Video
Updated: Jun 25, 2025

Production of a SARS-CoV-2 Virus-Like-Particle System to Investigate Viral Life Cycles In Vitro
Published on: June 6, 2025
SARS-CoV-2 ORF3a drives dynamic dense body formation for optimal viral infectivity
Stella Hartmann1,2, Lisa Radochonski1,2, Chengjin Ye3
1Department of Microbiology, University of Chicago, Chicago, IL, USA 60637.
Abstract:
SARS-CoV-2 uses the double-membrane vesicles as replication organelles. However, how virion assembly occurs has not been fully understood. Here we identified a SARS-CoV-2-driven membrane structure named the 3a dense body (3DB). 3DBs have unusual electron-dense and dynamic inner structures, and their formation is driven by the accessory protein ORF3a via hijacking a specific subset of the trans-Golgi network (TGN) and early endosomal membranes. 3DB formation is conserved in related bat and pangolin coronaviruses yet lost during the evolution to SARS-CoV. 3DBs recruit the viral structural proteins spike (S) and membrane (M) and undergo dynamic fusion/fission to facilitate efficient virion assembly. A recombinant SARS-CoV-2 virus with an ORF3a mutant specifically defective in 3DB formation showed dramatically reduced infectivity for both extracellular and cell-associated virions. Our study uncovers the crucial role of 3DB in optimal SARS-CoV-2 infectivity and highlights its potential as a target for COVID-19 prophylactics and therapeutics.
More Related Videos
Related Concept Videos
Rous Sarcoma Virus (RSV) and Cancer
RSV is a retrovirus that contains two copies of a plus-strand RNA genome. Its genome consists of four main open...
Viral Structure
Leaky Scanning
Viral Mutations
Immune Response Against Viral Pathogens
NK Cells
NK cells are a crucial part of our innate immune system, acting as the first line of defense against viral infections. These cells can recognize and kill infected cells without prior exposure to the virus, effectively slowing down the spread of infection. Additionally, NK cells produce proinflammatory...
Viral Recombination

