Oncogene expression in isogenic, EBV-positive and -negative Burkitt lymphoma cell lines

To elucidate the mode of action of Epstein-Barr virus (EBV), we have examined the possibility that EBV infection may lead to a change in oncogene expression. Levels of oncogene-related RNA were compared in the Burkitt lymphoma(BL)-derived, EBV-negative cell line BJAB and in two isogenic, EBV-converted sublines of BJAB whose growth characteristics differ from the EBV-negative parent line. The oncogenes c-myc, Ha-ras, and Blym were each found to be expressed at equally high levels in the three cell lines. This suggests that the mechanism of action of EBV in altering the growth properties of lymphoid cells is not dependent on the induction of cellular oncogenes. In addition, since the 8,14 chromosomal translocation has been related to increased c-myc expression in BL cells, a karyotype analysis was done to confirm the initial report of a normal karyotype in BJAB cells. Chromosomes 8 and 14 were seen to be normal. Thus, BJAB cells are a BL cell line in which the elevated expression of c-myc is independent not only of EBV but also of translocations involving chromosome 8.