Studies on the biosynthesis of TMV

Summary The replicative form and the replicative intermediate of TMV-RNA were isolated from synchronously infected tobacco leaves, labeled with H³-uridine for 1 hour. The replicative form is over 90% resistant to RNase and sediments slightly slower than the 16S ribosomal RNA. Sucrose gradient centrifugation of the thermally denatured replicative form revealed that it contains strands of the same size as single-stranded TMV-RNA. The replicative intermediate showed only partial resistance to RNase and heterogeneous sedimentation behavior in sucrose gradients. After mild RNase treatment the replicative intermediate sedimented homogeneously, and with an S value slightly lower than the replicative form.The following abbreviations are used RF replicative form - RI replicative intermediate - STE 0.1 M NaCl-1 mM Tris-HCl-1 mM EDTA, pH 7.4 - SSC 0.15 M NaCl-0.015 M sodium citrate, pH 7.0 - 10xSSC and 0.1xSSC tenfold concentrated and tenfold diluted SSC respectively - MAK methylated albumin coated kieselguhr