A method for isolation of oligo(uridylic acid)-containing messenger ribonucleic acid from Hela cells

Abstract
When cytoplasmic polyadenylated RNA [poly (A+) RNA] from [human cervical cancer] HeLa cells was treated with RNase H and oligo(dT) to remove its 3''-poly(A) tail, an increased binding to poly(A)-agarose was observed. The bound material, which comprised 4-6% of the initial RNA, contained 65-80% of the oligo(U) sequences generated by RNase T1 digestion. Oligo(U) isolated from the bound fraction was 83% U and had a U/G ratio of 33. In contrast, oligo(U) from the unbound material was 77% U and had a U/G ratio of 13, suggesting that it is shorter and less U rich than the oligo(U) in the bound fraction. On sucrose gradients, oligo(U+) RNA consistently sedimented with a larger s value than oligo(U-) RNA. The oligo(U) content of oligo(U+) RNA suggests one oligo(U) tract of 33 nucleotides per RNA molecule of 2000-3000 residues.