Epstein-Barr virus recombinants from overlapping cosmid fragments

Area of Science:

• Virology
• Molecular Biology
• Genetics

Background:

• Epstein-Barr virus (EBV) is a human herpesvirus implicated in various cancers.
• Replication-competent EBV genomes are essential for studying its biology.
• Previous methods for EBV genome reconstruction faced limitations in efficiency and completeness.

Purpose of the Study:

• To develop a method for generating a complete, replication- and transformation-competent Epstein-Barr virus (EBV) type 1 genome.
• To selectively recover EBV recombinants incorporating specific type 1 EBV genes (EBNA LP and EBNA 2).
• To investigate the efficiency of homologous recombination for reconstructing EBV genomes.

Main Methods:

• Cloning of overlapping type 1 EBV DNA fragments into cosmids.
• Transfection of cosmid DNA and an EBV replication activator (Z) into P3HR-1 cells (harboring type 2 EBV).
• Selective recovery of EBV recombinants by transforming primary B lymphocytes, followed by PCR and immunoblot analyses.

Main Results:

• Generated EBV recombinants with type 1 EBNA LP and EBNA 2 genes, capable of transforming primary B lymphocytes.
• Identified recombinants incorporating additional type 1 EBV DNA fragments beyond the transformation marker.
• Observed increased incorporation frequencies for specific type 1 genes (EBNA 3A, EBNA 3C) compared to previous methods.

Conclusions:

• The cosmid-based transfection system efficiently generates replication- and transformation-competent EBV type 1 recombinants.
• This method facilitates the study of EBV gene function and recombination mechanisms.
• The findings provide a robust platform for future EBV research and therapeutic development.