| Abstract |
Synchronized cat kidney cells chronically infected with feline leukemia virus (FeLV) were used to study virus production, the synthesis of group specific antigen (gag) and envelope (env) proteins, the expression of env protein on the cell surface during the cell cycle, and the stability of viral RNA. As detecting method, we developed the radioimmunoassay (RIA) system using beta-emission of ¹³¹I and demonstrated the validity of this system by comparison with routine RIA system using gamma-emission of ^125I. The produced virus was analysed by developed RIA interval was determined by measuring reverse transcriptase activity. The results show that infected cells produce the complete virus particle containing products of gag, env and pol genes of FeLV, and maximum virus production occurs during mitosis of synchronized cells. Labeling of the cell surface of synchronized cells with ¹³¹I shows that the amount of gp70^env on the cell surface parallels cellular growth. Therefore, the cell cycle-dependent release of virus is not petition RIA of synchronized cells with ¹³¹I-labeled viral proteins was used to measure viral protein synthesis during the cell cycle. The rate of synthesis of gag protein shows three peaks, corresponding to the G₁late S and late G₂phase of cell cycle. But the rate of synthesis of env protein dose not change, suggesting that in these cells the synthesis of these two gene products sharply from 8 hours after treatment, and the late S and G₂peaks of gag protein synthesis were disappeared. This shows the stability of viral RNA for about 6 hours in the absence of continuing viral RNA synthesis. |
