Polysome binding of RBCS, ACTIN, and JIP23 transcripts in rabbit reticulocyte lysates translating the RBCS, ACTIN, or JIP23 model transcripts. The translation mixtures were supplemented with either JIP60 (A) or its RIP-UP (B), RIP30 (C), and eIF4E (D) domains (+) or buffer (−). Then, polysomes were Mg2+-precipitated, and RNA present in the pellet and supernatant fractions was extracted with phenol and precipitated with ethanol. Quantification of mRNAs was made by Northern hybridization with gene-specific probes. Percentages refer to total transcript levels found in incubation mixtures lacking JIP60, RIP-UP, RIP30, and eIF4E, respectively, set as 100. Error bars represent the mean ± SD of three independent experiments.