Tethering of TNRC6 proteins to mRNA causes strong repression of protein synthesis and partial mRNA degradation. (A) Indicated HA- or NHA-tagged TNRC6 proteins were coexpressed into HEK293 cells with RL-5BoxB, FL-Con, and (in some transfections) GFP reporters. (Upper panel) RL expression was normalized to the activity of FL and is shown as the percentage of activity seen in the presence of HA-TNRC6C. Tethering of NHA-LacZ protein, frequently used as an additional control (see Figs. 6 and 8), did not repress protein synthesis. (Lower panel) Representative Western analysis of expressed proteins, performed with anti-HA Ab. (B) Northern blot analysis of RL-5BoxB and GFP mRNAs levels. (Upper panel) PhosphorImaging quantification of RL-5BoxB mRNA, normalized to GFP mRNA. (Bottom panels) Representative Northern blot analysis. Values in A and B are means from three independent experiments. Values for cells expressing HA-tagged proteins were set to 100%.
