Ron A, Horovitz O, Sarov I
J Mol Evol. 1976 Aug 3;8(2):137-42. doi: 10.1007/BF01739099.
Exponential growing Tetrahymena pyriformis organisms were labelled with (3H) uridine or (3H) adenosine. The labelled RNA was extracted and isolated by affinity chromatography on poly-uridylic-acid sepharose and further analysed by means of sucrose gradient centrifugation and RNase digestion. Experimental evidence proved the existence of RNase resistant poly adenylic-acid fragments in the RNA of Tetrahymena cells. This poly adenylic-acid segment has a sedimentation rate of 4-5 S and would be localised in the 10-12S region of the RNA which is probably the m-RNA.