Figure 3.

Hfq impedes the poly(A) shortening activity of PNPase and RNase II. Digestion of 5′-labelled polyadenylated ΔrpsO mRNA in the absence (–Hfq) and presence of 1 µmol/l Hfq (+Hfq) was performed as described in Materials and methods. Aliquots were removed at 1, 2, 5, 10 and 20 min digestion. ‘C’ indicates the non-digested sample. (A) Digestion with 0.2 pmol RNase II and (B) with 2 pmol PNPase. We chose conditions in which each enzyme exhibits comparable exoribonuclease activity and in which the activity was limited. Lanes with sequence ladders and non-polyadenylated mRNA are not shown. (C) Quantification of experiments shown in (A) and (B).