Epstein-Barr virus (EBV) infects over 90% of the world's population, and like other herpesviruses it establishes a permanent latent infection in the host. The native B-lymphocyte is the preferred target of EBV, which after differentiation into memory B-cells contains the latent reservoir of virus subsequent to the resolution of acute infection.

Several malignancies have been associated with EBV infection, including nasopharyngeal carcinoma, endemic Burkitt's lymphoma, AIDS-related lymphoma and post-transplant lymphoproliferative disorder, among others. During the latent phase of infection and in EBV-associated tumors, a limited number of viral proteins are expressed, among them the Epstein-Barr nuclear antigen 3 (EBNA3) family of proteins. Of these three proteins, two (EBNA3A and 3C) are absolutely indispensable for viral transformation of B-lymphocytes, and all appear to significantly contribute to maintaining the viability of transformed cells, suggesting an important role in oncogenesis.

These viral proteins interact with numerous cellular factors, including transcriptional regulators, cell-cycle components and cytoskeletal elements. Additionally, the EBNA3 family of proteins appears to regulate the expression of other crucial viral proteins and modulate their functions, creating an intricate system of checks and balances critical for lifelong survival of the virus in the host.

from Epstein-Barr Virus: Latency and Transformation

Further reading:

• Epstein-Barr Virus
• RNA Interference and Viruses
• Virology publications

Labels: AIDS-related lymphoma, EBNA3, Endemic Burkitts lymphoma, nasopharyngeal carcinoma, Post-transplant lymphoproliferative disorder