Enhancement of Inoue-Melnick virus synthesis by 5-bromodeoxyuridine in human meningioma (MG-1) cells

The authors found remarkable enhancement of Inoue-Melnick virus (IMV) synthesis by 5-bromodeoxyuridine (BUDR) in human meningioma (MG-1) cells, a virus-producer line of type 1 IMV. Treatment with BUDR resulted in rapid and abundant synthesis of infectious IMV in MG-1 cells. The titer of the cell-associated virus in treated cells increased approximately 6.0 log 10 compared with that in untreated cells. Immunofluorescent antibody tests revealed that IMV-associated late antigen was induced by BUDR in the cytoplasm of approximately 50% of treated cells. A clonal difference was also found in the enhancement of BUDR on the IMV synthesis in MG-1 cells. The most remarkable enhancing effect of BUDR was observed in the clone C line, and a herpes-type virus was detected by negative-staining electron microscopy in the culture fluid of the clone C treated with BUDR.