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Isolation and characterization of an EBV superinfection-enhanced, host-cell-coded, 53,000-dalton protein
Abstract:
Microsomal membrane fraction proteins with enhanced synthesis after P3HR-1 Epstein-Barr virus (EBV) superinfection of Raji cells were identified with [35S]-methionine labeling and SDS-PAGE. One 53,000-dalton protein, which was found in both the microsomal membrane and cytosol fractions, was purified by ion-exchange chromatography, and specific rabbit antisera were prepared to it. This protein was found to be present in Raji cells, but its expression was enhanced after P3HR-1 EBV superinfection. It was more abundant in the cytosol than in the microsomal membrane fraction of the cell, and its synthesis was not affected by treatment of the cells with phosphonoacetic acid. It was present in several EBV-genome-negative cell lines and in activated B lymphocytes and consequently represents a host-cell-coded protein which is enhanced by EBV superinfection or by lymphocyte activation.
Insights
Researchers identified a 53 kDa host-cell protein whose synthesis increases after Epstein-Barr virus (EBV) infection in Raji cells. This protein is also upregulated by B lymphocyte activation, indicating a role in cellular response to viral infection and immune activation.
Area of Science:
- Virology
- Cell Biology
- Immunology
Background:
- Epstein-Barr virus (EBV) is a human herpesvirus known to infect B lymphocytes.
- Understanding host-cell responses to EBV infection is crucial for deciphering viral pathogenesis and immune evasion strategies.
Purpose of the Study:
- To identify host-cell proteins with altered synthesis following EBV superinfection of Raji cells.
- To characterize a specific 53 kDa protein upregulated by EBV infection and lymphocyte activation.
Main Methods:
- [35S]-methionine labeling and SDS-PAGE to identify proteins with enhanced synthesis.
- Ion-exchange chromatography for protein purification.
- Preparation of specific rabbit antisera for protein detection.
- Analysis of protein expression in various cell lines and activated lymphocytes.
Main Results:
- A 53 kDa protein was identified in both microsomal membrane and cytosol fractions, with enhanced synthesis after P3HR-1 EBV superinfection of Raji cells.
- The protein was more abundant in the cytosol than in the microsomal membrane fraction.
- Protein synthesis was not affected by phosphonoacetic acid treatment, suggesting a host-cell origin.
- The protein was present in EBV-genome-negative cell lines and activated B lymphocytes.
Conclusions:
- The 53 kDa protein is a host-cell-coded protein.
- Its expression is enhanced by EBV superinfection and B lymphocyte activation.
- This protein may play a role in the host response to EBV and immune activation.