Intracellular Fate of Mengo Virus Ribonucleic Acid

Abstract

Homma , M. (The Wistar Institute, Philadelphia, Pa.), and A. F. Graham . Intracellular fate of Mengo virus ribonucleic acid. J. Bacteriol. 89: 64–73. 1965.—P 32 -labeled, purified preparations of Mengo virus adsorbed rapidly and irreversibly to L cells maintained in suspension cultures. At intervals after adsorption of labeled virus, the total ribonucleic acid (RNA) of infected cells was extracted by a phenol technique. Infectivity titrations on this RNA showed that it retained its full biological activity during the early part of the eclipse period. Sucrose gradient sedimentation analyses showed also that this RNA lost none of its structural integrity throughout the eclipse period. No evidence was found for a double-stranded structure involving parental RNA. When cells infected with P 32 -labeled virus were broken open during the first 7 hr after infection, no more than 20% of the parental RNA could be digested with ribonuclease. Electron microscopy indicated that only one particle in five of the purified viral populations was infectious. It is suggested that only one of five adsorbed virus particles was uncoated and that its RNA remained in the cell in an undegraded form during the eclipse period. The other adsorbed particles were not uncoated and took no part in the process of infection. The maximal transfer of parental RNA to progeny virus was 4.5%.