Herpes simplex virus expressing Epstein-Barr virus nuclear antigen 1

Area of Science:

• Molecular Virology
• Gene Expression Systems
• Recombinant DNA Technology

Background:

• Epstein-Barr virus (EBV) nuclear antigen 1 (EBNA1) is essential for viral DNA replication and maintenance.
• Efficient expression of EBNA1 is challenging in standard cell culture systems.
• Herpes simplex virus 1 (HSV-1) alpha genes offer a powerful, inducible promoter system for gene expression.

Purpose of the Study:

• To construct and characterize a chimeric gene vector for enhanced EBNA1 protein expression.
• To investigate the regulation and inducibility of the chimeric alpha 4-EBNA1 gene.
• To assess the utility of this vector for producing high levels of EBNA1.

Main Methods:

• Fusion of EBV EBNA1 open reading frame with HSV-1 alpha 4 gene regulatory elements.
• Introduction of chimeric genes into L cells and integration into the HSV-1 genome via thymidine kinase selection.
• Analysis of protein expression, electrophoretic and immunologic properties, and viral regulation.

Main Results:

• Chimeric constructs expressed a protein identical to authentic EBNA1, confirming correct initiation of translation.
• Expression of chimeric alpha 4-EBNA1 genes was inducible by HSV-1 infection and regulated as alpha genes.
• Recombinant viruses exhibited 50- to 100-fold higher EBNA1 expression compared to natural EBV infection, without affecting HSV-1 protein expression.

Conclusions:

• The developed chimeric alpha 4-EBNA1 gene vector is a stable and highly efficient system for EBNA1 production.
• This vector system demonstrates inducible and regulated expression, mimicking HSV-1 alpha gene kinetics.
• The enhanced EBNA1 expression has potential applications in virology research and the study of EBV-associated diseases.