Expression of BARF1 gene encoded by Epstein-Barr virus in nasopharyngeal carcinoma biopsies

We reported previously that the EBV BARF1 open reading frame encodes a M-r 31,000-33,000 protein (p31) with potential transforming and oncogenic prope rties. This gene was found capable of transforming both: (a) the rodent fib roblast lines Balbc/3T3 and NIH3T3 into cells producing aggressive tumors i n newborn rats; and (b) the human EBV-negative B-cell Line Louckes into cel ls leading to small tumors, which disappeared 3 weeks after injection. Our recent study showed that BARF1 ORF expression may confer the property of im mortalization to primary kidney epithelial cells (M, X, Wei et al., Oncogen e, 14: 3073-3081, 1997), Because this suggested that BARF1 could be involve d in epithelial malignancy, we investigated its transcriptional and transla tional expressions in Algerian nasopharyngeal carcinoma (NPC) biopsies by r everse transcription-PCR and immunoblotting using rabbit polyclonal antiser a prepared against two synthetic peptides corresponding to distinct, predic ted epitopes of the BARF1 protein (NGGVMKEKD, amino acids 172-180, and GKND KEE, amino acids 203-209), The BARF1 ORF was found to be transcribed and tr anslated in >85% of our NPC biopsies, with high p31 protein Level detected in several NPC patient biopsies as well as in NPC-derived xenografts, Our o bservation of BARF1 expression in a large proportion of NPC epithelial cell s suggests that this EBV gene might play an important role in the malignant transformation of human epithelial cells in vivo.