EFFECT OF A 10-AMINO-ACID DELETION ON THE ONCOGENIC ACTIVITY OF LATENT MEMBRANE-PROTEIN-1 OF EPSTEIN-BARR-VIRUS

A previous study has shown that the BNLF1 of Epstein-Barr virus (EBV), isolated from a nasopharyngeal carcinoma biopsy (BNLF1-1510), was able to transform Balb/3T3 cells,On the other hand, BNLF1 of a prototype v irus B95-8 (BNLF1-958) was not transforming unless the gene was transc ribed from a strong promoter, In this study, we have generated chimeri c BNLF1 by exchanging the DNA fragments between BNLF1-1510 and BNLF1-9 58 and examined their expression and transformation ability in Balb/3T 3 cells, Results showed that transformation of Balb/3T3 cells by BNLF1 -1510 was not due to the excessive expression of the gene, Transfectio n of Balb/3T3 cells with chimeric BNLF1 showed that the genes with 3' 453 bp sequence of BNLF1-1510 were oncogenic to the cells, Study also revealed that changing the numbers of the 33 bp repeats in the 3' regi on of the two BNLF1s did not affect the transformation characteristics . On the other hand, deletion of a 30 bp sequence of BNLF1-958, which is absent in BNLF1-1510, changed the gene oncogenic to oncogenic and i nsertion of sequence into BNLF1-1510 abolished the transformation abil ity, BNLF1 without this 30 bp sequence was also found in the tumours o f other EBV-related neoplastic disease, suggesting that absence of thi s 30 bp sequence in BNLF1 may be associated with the oncogenesis of th ese diseases.