Epstein-Barr virus with transforming and early antigen-inducing ability originating from nasopharyngeal carcinoma: mapping of the viral genome.

Epstein-Barr virus (EBV) from a human hybrid epithelial cell line (NPC-KT), derived from the fusion of human adenoidal cells and EBV genome-containing primary nasopharyngeal carcinoma cells (NPC) has both transforming and early antigen (EA)-inducing abilities. EBV DNA from NPC-KT cells was partially digested with TaqI and ligated to the cloning vector pJB8 at the ClaI site. This cosmid library encompassed the whole genomic DNA of the virus except for several kb of the terminal fragments. The identification and location of each of the cloned DNA fragments have been defined by hybridization to blots prepared with B95-8 and NPC-KT virion DNA. Defective heterogeneous restriction enzyme fragments of the viral DNA were not identified in any of the cosmid clones nor detected in hybridizations to virion DNA, which indicates that a single virus population derived from the NPC tissue has both transforming and EA-inducing activities.