PARTICIPATION OF SENDAI VIRUS RIBONUCLEOPROTEIN IN VIRUS-SPECIFIC POLYSOME FORMATION

Unwound and partially deproteinized parental Sendai virus ribonucleoprotein (ρ{variant} = 1.38 g/cm3) in the cytoplasm of Sendai virus-infected Ehrlich tumor cells was shown to associate with ribosomes to form a complex with buoyant density ρ{variant} = 1.45 g/cm3 and sedimentation coefficient 160 S. The complex involves virus-specific newly synthesized RNA. Evidence that this complex contains functional viral polysomes capable of translation is provided by experiments that show: (a) the ρ{variant} = 1.45 complex incorporates labeled amino acids into acid-insoluble material; (b) the complex is broken down upon addition of EDTA, and the ρ{variant} = 1.38 parental virus component is released after such treatment; (c) the complex is broken down upon addition of ribonuclease; (d) polysome structures in close connection with unwound virus ribonucleoprotein are seen when the complex is investigated in the electron microscope; (e) the ρ{variant} = 1.45 complex is not found in uninfected cells and infected nonsusceptible cells. Parental virus ribonucleoprotein released from the complex after EDTA and ribonuclease treatment is closely associated with pulse-labeled protein(s). © 1969.