Figure 2. DnaG influences the degradation properties of the Csl4-exosome but not of the Rrp4-exosome, and confers poly(A) specificity to the Csl4-exosome. (A) A phosphorimage of a 16% polyacrylamide gel with degradation assays containing 8 pmol radioactively labeled poly(A) 30-mer and 0.3 pmol of the Csl4-exosome or the Csl4-exosome supplemented with DnaG. The time of incubation at 60°C is also indicated (in min). The poly(A) substrate and the degradation products (degr. products) are marked on the right side. The size of the degradation products was previously estimated.²⁶ Control, negative control without protein. (B) Graphical representation of the results shown in (A) and from two additional independent experiments. (C) A phosphorimage of a 16% polyacrylamide gel with degradation assays containing 8 pmol radioactively labeled poly(A) 30-mer and 0.3 pmol of the Rrp4-exosome or the Rrp4-exosome supplemented with DnaG. For further descriptions, see (A). (D) Graphical representation of the results shown in (C) and from an additional independent experiment. (E‒G) Graphs showing the relative amount of the remaining substrate (in %) against the time (in min) in degradation assays (data from three independent experiments). In each reaction, 0.3 pmol protein complex was used. The protein complexes, labeled RNAs and non-labeled competitors, and their amounts per reaction mixture are indicated. (H) A phosphorimage of a 16% polyacrylamide gel with degradation assays containing the proteins indicated above the panel. 0.3 pmol of either Rrp41, Rrp42, Rrp4, Csl4, DnaG, the hexameric ring or the DnaG-Csl4-exosome were incubated for 10 min at 60°C with 8 fmol (lanes 1‒7) or 1 pmol (lanes 8‒12) radioactively labeled poly(A) 30-mer. Control, negative control without protein. Only His-tagged proteins were used for the experiments in this figure.