Effect of band V RNAi on sedimentation and U insertion. In parallel, mitochondrial extracts were prepared from a clonal band V RNA cell line, noninduced or 5 days postinduction, and were resolved by glycerol gradient centrifugation. (A and B) Adenylylation assays, following deadenylylation, of fractions from the noninduced (A) and induced (B) band V RNAi cells. (C) The peak ∼20S fractions, which had similar amounts of band IV ligase, were analyzed for full-round U insertion.