Abstract
We report a new rodent cell‐transforming gene, presumably involved in viral replication, encoded by Epstein‐Barr virus. We previously showed that the corresponding open reading frame BARF1 is transcribed before the onset of viral DNA synthesis, and translated into a 33 kd early polypeptide (p33). Here we show that recombinant plasmids containing the BARF1 induce morphological change, anchorage‐independent growth and tumorigenic transformation of established mouse fibroblast lines. The BARF1‐transformed cells and the tumour tissues isolated from new‐born rats after injection of such transformed cell both express p33. Transforming activity was obtained from either the genomic fragment or the cDNA sequence.