FIG 1.

RACK1 is essential for efficient translation of capped mRNAs in vitro. (A) Scheme representing the in vitro translation strategy used. (B) Diagrams of the mRNA reporters employed. (C) Absolute luciferase counts from in vitro translation of the reporters. Values are shown on a logarithmic scale. A.U., arbitrary units. (D) Representative Western blot assessing RACK1 protein depletion in samples used for in vitro translation. scr, scrambled sequence. (E) Quantification of RACK1 protein in the samples. RACK1 protein levels were normalized to β-actin levels. (F) Quantification of the translational efficiency, in vitro, of cap-, TOP-, and short loop-regulated mRNA reporters under conditions of RACK1 downregulation. (G) Quantification of the in vitro translational outputs of long loop-, uORF-, and HCV IRES-regulated reporters upon RACK1 downregulation. Data are from a representative assay. At least four independent replicates were performed for each assay. Means and standard deviations are shown. Statistical significance was determined by the t test. P values are indicated as follows: *, <0.05; **, <0.01.