THE LYTIC CYCLE OF EPSTEIN-BARR-VIRUS IN THE NONPRODUCER RAJI LINE CAN BE RESCUED BY THE EXPRESSION OF A 135-KILODALTON PROTEIN ENCODED BY THE BALF2 OPEN READING FRAME

In Epstein-Barr virus (EBV)-carrying nonproducer Raji cells, the induc tion of the viral replicative cycle by chemical treatment is limited t o only the early stage and viral DNA synthesis is totally inhibited. W e previously showed the absence of two messenger RNAs that are encoded by the Bam HI-A fragment of the EBV genome and that correspond to ope n reading frames BALF2 and BARF1 in chemically induced Raji cells. Sin ce the BALF2 gene encodes a 135-kDa DNA binding protein which was immu noprecipitated by antibody against ICPS protein, a key protein in herp es simplex virus replication, we asked whether the lack of productive cycle in Raji cells is due to the absence of expression of the BALF2 g ene. We transfected the Raji cell line with the BALF2 gene, After chem ical induction, the BALF2-transfected cells expressed not only early a ntigens but also late antigens. In these cultures, the viral particles were detected by electron microscopy. The expression of late antigens was completely inhibited by arabinofuranosylthymine, which is a speci fic inhibitor of viral DNA replication, The BALF2 gene might play an e ssential role in the induction of the EBV-lytic cycle.