Polypeptide synthesis and phosphorylation in Epstein-Barr virus-infected cells

Area of Science:

• Virology
• Molecular Biology
• Cell Biology

Background:

• Raji cells, derived from Burkitt lymphoma, harbor Epstein-Barr virus (EBV) genomes.
• Superinfection with EBV in Raji cells provides a model to study viral protein synthesis and host cell response.

Purpose of the Study:

• To characterize the protein synthesis patterns following EBV superinfection in Raji cells.
• To identify EBV-induced proteins and their temporal expression during infection.
• To investigate the effect of antiviral agents on EBV-induced protein synthesis.

Main Methods:

• Superinfection of Raji cells with Epstein-Barr virus.
• Analysis of newly synthesized proteins using gel electrophoresis to determine molecular weights.
• Assessment of protein synthesis rates and phosphorylation.
• Treatment with antiviral drugs, including acyclovir and phosphonoacetic acid.

Main Results:

• EBV superinfection induced the synthesis of 29 viral proteins (155,000 to 21,000 MW) and shut off host protein synthesis within 6-9 hours.
• Viral proteins were classified into early (8 proteins by 6h), intermediate (2 proteins by 9h), and late (5 proteins by 12h) classes.
• A fourth class, 'persistent' proteins, were present before and after infection. Antiviral drugs inhibited specific intermediate and late proteins. Seven polypeptides were phosphorylated post-infection.

Conclusions:

• EBV superinfection orchestrates a complex program of viral protein synthesis, including distinct temporal classes.
• Host protein synthesis is significantly suppressed following EBV superinfection.
• Antiviral agents targeting viral DNA replication can inhibit the expression of specific EBV-induced proteins.