CCR4 and CAF1 deadenylases have an intrinsic activity to remove the post-poly(A) sequence

miRNAs can induce the removal of a non-A sequence downstream from the poly(A) tail in S2 cells. (A) Schematic representation of Rluc-let-7-A₅₀-HhR and Rluc-let-7-A₅₀C₁₀-HhR. These reporter RNAs include Renilla luciferase (Rluc) ORF, eight let-7 target sites, and hammerhead ribozyme. The subscripts show the length of an RNA sequence including the shown base. (B) Northern blot analysis of the reporter RNAs shown in A. Expression of pri-let-7 induced degradation of the reporter RNAs in GFP knockdown (mock). In Dcp2 knockdown, deadenylated RNAs were detected dependently on expression of pri-let-7.