Differential Effects of Inhibitors on the Steps Leading to the Formation of Sv40 Tumor and Virus Antigens

Abstract

The demonstration that hamster (1-3) and human (2) cells transformed by SV40 virus synthesize a new antigen under control of the virus genome led to the discovery that the same antigen is also formed during the normal replication cycle of SV40 in green monkey cells (3-5). As the sequence of SV40 replication had been previously studied (6, 7), it was quickly ascertained that this new tumor or T antigen is formed during the latent period and that synthesis of T antigen precedes that of the virus or V antigen found in the SV40 virion (5).From our earlier investigations of the inhibitory effect of 5-fluorouracil and 5-fluorodeoxyuridine on the synthesis of V antigen and infectious virus (7), we were led into a study of the effects of these and other DNA antagonists and inhibitors on the synthesis of both T and V antigens in an effort to obtain information concerning the nature and role of the T antigen in the synthesis of SV40 virus as well as its formation in cells transformed by the virus but free of infectious virions. Materials and MethodsViru*.--Stocks of SV40 were prepared in primary African green monkey kidney cells (GMK) growing in 16-ounce bottles. When cytopathic effects (CPE) involved 75 to 100 per cent of the cells, the cultures were disrupted by quick-freezing and thawing. After clarification by centrifugation at 3000 g for 5 minutes at 4°C, the virus was dispensed in ampoules which were sealed; the virus was quickly frozen, and stored at --90°C. "liters of the virus stocks were obtained using the plaque assay previously described (8); all stocks employed in this study contained 108 to 10 T plaque-forming units (PFU) per ml. The tumorigenic potential of this virus strain has been reported from this laboratory (9), as has the growth cycle of the virus in GMK cells (7).

The EB virus in relation to infectious mononucleosis

“…This antigen is another early product of viral replication and is independent of viral DNA synthesis (Gergely et al, 1971). As in the case of the cell membrane antigens it has some resemblance to antigens observed in cell cultures of tumours induced experimentally by oncogenic DNA viruses (Rapp, Butel, Feldman, Kitahara, and Melnick, 1965;Rapp, 1968). …”

Genetic Evidence for a Temperature-Sensitive Lesion in the Adenovirus 7 Region of the PARA Genome

“…The plaque-purified progeny no longer induce SV40 T antigen. Ad type 7 [20] which has been passed 7 times in GMK cells, purified by centrifugation in a CsCl gradient, and passed 9 times in CV-1 cells. Viral assays.…”

Effect of adenovirus type 12 on tumor induction by SV40 and para (defective SV40)

“…SV40 was the Baylor reference strain described previously (Rapp et al, 1965a). It had been grown in CV-1 cells, a stable line derived from green monkey kidney (GMK) cells.…”