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Updated: Jun 11, 2025
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Use of In vivo Imaging to Monitor the Progression of Experimental Mouse Cytomegalovirus Infection in Neonates
Published on: July 6, 2013
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Secondary Envelopment of Human Cytomegalovirus Is a Fast Process Utilizing the Endocytic Compartment as a Major
Tim Bergner1, Laura Cortez Rayas2, Gesa Freimann1
1Central Facility for Electron Microscopy, Ulm University, 89081 Ulm, Germany.
Biomolecules
|September 28, 2024
Summary
Human cytomegalovirus (HCMV) uses endocytic membranes for secondary envelopment. This process rapidly delivers plasma membrane components to the viral assembly complex for efficient virion formation.
Area of Science:
- Virology
- Cell Biology
- Membrane Trafficking
Background:
- Secondary envelopment of human cytomegalovirus (HCMV) is crucial for infectivity but its membrane source remains debated.
- Previous studies suggested diverse origins, including the trans-Golgi and endosomal pathways, for the viral envelope.
Purpose of the Study:
- To investigate the role of endocytic membranes in HCMV secondary envelopment.
- To determine the origin and trafficking dynamics of membranes used for HCMV envelope acquisition.
Main Methods:
- Wheat germ agglutinin (WGA) pulse labeling of plasma membrane glycoproteins.
- Tracking WGA-labeled membranes using light microscopy and transmission electron microscopy (TEM) during HCMV infection.
- Analysis of capsid association with labeled membrane compartments within the cytoplasmic viral assembly complex (cVAC).
Main Results:
- WGA labeling identified endocytic compartments (early endosomes, multivesicular bodies, recycling endosomes) and trans-Golgi within the cVAC.
- Nearly 90% of capsids in secondary envelopment and 50% of enveloped capsids were WGA-positive within 90 minutes.
- HCMV infection induces significant remodeling of the endocytic compartment, facilitating virion morphogenesis.
Conclusions:
- The endocytic compartment serves as the primary membrane source for HCMV secondary envelopment.
- Endocytosed membranes are rapidly transported from the plasma membrane to the cVAC for efficient virion envelopment.
- Secondary envelopment is a rapid process optimized by the remodeled endocytic pathway during HCMV infection.
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