Biophysical studies on double-stranded RNA from turnip yellow mosaic virus-infected plants

Summary Double-stranded RNA was isolated in mg quantities from TYMV-infected cabbage plants by a modified phenol procedure. Chromatography of the RNA on methylated albumin and hydroxyapatite is described. The base composition (A=21.3; U=21.2; G=28.8; C=28.7) was in good agreement with the values expected for a double-stranded RNA consisting of TYMV RNA and a strand complementary to it. The buoyant density of the RNA in Cs₂SO₄ was 1.617 g/cm³. Single-stranded TYMV RNA banded at 1.642 g/cm³ in Cs₂SO₄. The RNA sedimented in the analytical ultracentrifuge with an average sedimentation coefficient of 10–11 s. Absorbance as a function of temperature was determined in several different media. The absorbance-temperature profiles were typical of those expected for double-stranded RNA. Denatured RNA was examined by equilibrium density gradient centrifugation.