Poly(A)‐Containing RNA in Tetrahymena pyriformis

Abstract

Poly(A)-containing RNA with sedimentation coefficients in the range 10-45 S and 10-35 S (Mr [molecular ratio] 0.2-3.3 .times. 106 and .apprx. 0.2-2.2 .times. 106) are present in the nucleus and cytoplasm of T. pyriformis, respectively. The poly(A) segments present in both nuclear and cytoplasmic poly(A)-containing RNA have a chain length of 80-150 nucleotides. Significant amounts of high-molecular-weight poly(A)-containing RNA (35 S, Mr 2.2 .times. 106) are found in the post-polysomal fraction of the cytoplasm (messenger ribonucleoprotein particles) and also in large polysomes. In order to exclude the possibility that these high-molecular-weight species are products of non-specific aggregation, RNA preparations were submitted to severe denaturing conditions before analysis and all electrophoreses were carried out in the presence of 95% vol/vol formamide.