The ribozyme cleavage products contain a 5′-phosphate end. (A) The indicated gel-purified uniformly labeled reaction products, corresponding to each end of the IRES transcript, were self-ligated in the presence of T4 RNA ligase. The ligation products were fractionated in denaturing gels, parallel to control samples incubated in the absence of ligase. (B) A similar study carried out with the three digestion products of the central domain, of 200, 130, and 100 nt. Brackets point to retarded ligation products; thin lines denote RNA size markers. (C) Summary of the ligation test assay. The gel-purified product resulting in the formation of ligation products, depicted by a thick line, contains 5′-P and 3′-OH residues. The size of each fragment (in a number of nucleotides) is indicated.
