RNA synthesis in the L cell-SV5 system

Comparative analysis of the ribonucleoprotein RNA synthesis was performed in two persistently infected L cell systems. In the first (LSV5-I), cells were infected with the cloned standard SV5 virus, in the second (LSV5-II), infecting virus had been enriched with defective interfering particles (DIP). The LSV5(I) system in its 40th-42nd passages was similar to LSV5(II) at the 2nd-3rd passage levels. There was shown that the ribonucleoprotein 3H-RNA synthesized falls into two classes: the minor corresponding to 50S viral RNA and the major revealing predominantly low molecular RNA. The decrease of the synthesis of the heavy viral RNA fraction and the prevalence of the low molecular RNA promoted the limitation of infection, the survival of cells and prolonged the carrier state. The possible correlation between low molecular RNA synthesis and DIP formation in the L cell-SV5 system is discussed.