Epstein–Barr virus latent genes

Abstract

Latent Epstein–Barr virus (EBV) infection has a substantial role in causing many human disorders. The persistence of these viral genomes in all malignant cells, yet with the expression of limited latent genes, is consistent with the notion that EBV latent genes are important for malignant cell growth. While the EBV-encoded nuclear antigen-1 (EBNA-1) and latent membrane protein-2A (LMP-2A) are critical, the EBNA-leader proteins, EBNA-2, EBNA-3A, EBNA-3C and LMP-1, are individually essential for in vitro transformation of primary B cells to lymphoblastoid cell lines. EBV-encoded RNAs and EBNA-3Bs are dispensable. In this review, the roles of EBV latent genes are summarized. The latent form of Epstein-Barr virus (EBV) relies on a small arsenal of genes to manipulate host cell genes and promote cancerous growth. Many people unknowingly harbor EBV, which remains latent in immune and epithelial cells after initial infection. The latent virus is harmless if it remains dormant but if it becomes reactivated it can contribute to a variety of different cancers and immune disorders. Myung-Soo Kang at the Sungkyunkwan University School of Medicine in Korea and Elliott Kieff of Harvard Medical School in the USA review current knowledge regarding the specific genes that become active in the latent virus. Their analysis reveals diverse parallel mechanisms by which EBV removes the blocks that inhibit cell division while at the same time thwarting the controlled ‘self-destruct’ mechanisms that act as a critical safeguard against cancer.