Related Experiment Video
Updated: May 19, 2026
In Vitro Analysis of Myd88-mediated Cellular Immune Response to West Nile Virus Mutant Strain Infection
Published on: November 27, 2014
Mutations in the West Nile prM protein affect VLP and virion secretion in vitro
Amanda E Calvert1, Claire Y-H Huang, Carol D Blair
1Arbovirus Diseases Branch, Division of Vector-Borne Diseases, Centers for Disease Control and Prevention, Public Health Service, US Department of Health and Human Services, Fort Collins, CO 80521, USA. zpz0@cdc.gov
Abstract:
Mutation of the West Nile virus-like particle (WN VLP) prM protein (T20D, K31A, K31V, or K31T) results in undetectable VLP secretion from transformed COS-1 cells. K31 mutants formed intracellular prM-E heterodimers; however these proteins remained in the ER and ER-Golgi intermediary compartments of transfected cells. The T20D mutation affected glycosylation, heterodimer formation, and WN VLP secretion. When infectious viruses bearing the same mutations were used to infect COS-1 cells, K31 mutant viruses exhibited delayed growth and reduced infectivity compared to WT virus. Epitope maps of WN VLP and WNV prM were also different. These results suggest that while mutations in the prM protein can reduce or eliminate secretion of WN VLPs, they have less effect on virus. This difference may be due to the quantity of prM in WN VLPs compared to WNV or to differences in maturation, structure, and symmetry of these particles.
Insights
Mutations in West Nile virus-like particle (WN VLP) prM protein prevent secretion. While prM mutations impact VLP release, they have a lesser effect on infectious West Nile virus (WNV) particle production and infectivity.
Area of Science:
- Virology
- Molecular Biology
- Cell Biology
Background:
- The West Nile virus (WNV) prM protein is crucial for proper viral particle assembly and secretion.
- Understanding prM protein function is key to developing antiviral strategies and vaccines.
Purpose of the Study:
- To investigate the impact of specific prM protein mutations on West Nile virus-like particle (WN VLP) secretion.
- To compare the effects of these mutations on WN VLP production versus infectious WNV replication and infectivity.
Main Methods:
- Site-directed mutagenesis was used to introduce mutations into the WN VLP prM protein (T20D, K31A, K31V, K31T).
- COS-1 cells were transfected to assess VLP secretion and protein localization (ER, Golgi).
- Infectious WNV with equivalent mutations was used to infect COS-1 cells to evaluate viral growth and infectivity.
- Epitope mapping was performed on WN VLPs and WNV prM.
Main Results:
- Mutations K31A, K31V, and K31T abolished WN VLP secretion, with proteins accumulating in the ER and ER-Golgi intermediate compartment.
- The T20D mutation impaired glycosylation, heterodimer formation, and WN VLP secretion.
- Infectious K31 mutant WNV showed delayed growth and reduced infectivity compared to wild-type (WT) virus.
- Distinct epitope maps were observed for WN VLP and WNV prM.
Conclusions:
- prM protein mutations significantly disrupt WN VLP secretion, affecting intracellular trafficking and particle formation.
- Mutations in prM have a less pronounced effect on infectious WNV replication and infectivity compared to VLP secretion.
- Differences in prM quantity, maturation, structure, or symmetry between VLPs and infectious virions may explain these distinct outcomes.
Related Concept Videos
01:25Arboviral Encephalitis
02:28Leaky Scanning