Xp54 and CAF1 repress translation independent of eIF4E and the 5′ cap. (A) Schematic of the tethered function assay. (FF) firefly luciferase, (Ren) Renilla luciferase. “Protein” represents GLD2-D242A (negative control), CAF1b, CAF1b DE-AA, or Xp54. (B) Schematic of the firefly luciferase reporters used. The IRES translation factor requirements are depicted. (C) Results of tethered function assay, normalized to “no MS2 protein” control (none, black bars). Three independent experiments were performed, with four oocyte replicates each time. Error bars represent 1 SD. Student's two-tailed t-test was used to compare the Xp54, CAF1b, and CAF1b DE-AA data to the no MS2 protein data for each reporter. For CAF1b, CAF1b DE-AA, and Xp54, the difference was highly significant (P < 0.005) only for the capped and PV IRES reporters.
