Epstein-Barr virus nuclear antigen 3 (EBNA-3)

Epstein-Barr virus nuclear antigen 3 (EBNA-3) is a family of three large viral proteins (EBNA-3A, -3B, and -3C) that are critical for the establishment and maintenance of Epstein-Barr virus (EBV) latency and the transformation of human B lymphocytes. These proteins function as potent transcriptional and epigenetic regulators by interacting with host cellular factors, most notably the Notch-signaling component RBP-Jk (CBF1), to reprogram host gene expression. EBNA-3A and EBNA-3C act as oncoproteins by cooperatively silencing tumor suppressor genes, such as p16INK4A and p14ARF, and inhibiting pro-apoptotic signals like Bim, thereby promoting uncontrolled cell cycle progression and survival. Conversely, EBNA-3B acts as a viral tumor suppressor in vivo, balancing the oncogenic potential of its family members to facilitate lifelong viral persistence without excessive lymphoproliferation. Clinically, the EBNA-3 family is associated with various EBV-related malignancies, including Burkitt's lymphoma, nasopharyngeal carcinoma, and post-transplant lymphoproliferative disorders. While no specific small-molecule inhibitors of EBNA-3 are currently FDA-approved, they are prominent targets for immunotherapeutic strategies such as adoptive T-cell transfer and experimental combinations of epigenetic modulators like vorinostat and proteasome inhibitors like bortezomib.

Other names

EBNA3 familyEBNA-3AEBNA-3BEBNA-3CBERF1BERF2BERF3EBNA3 proteinsBLRF3-BERF1BERF2A-BERF2BBERF3-BERF4

Epigenetic modulation of host genes, inhibition of host gene reprogramming, induction of apoptosis in latently infected cells, and enhancement of antigen presentation for T-cell recognition.