FIG. 4.

eIF4F but not eIFiso4F mediates TEV IRES function in a dicistronic mRNA. eIF4F/eIFiso4F-reduced wheat germ lysate was programmed with uncapped GUS-SL-Con₁₄₄-luc-A₅₀ mRNA (A) or uncapped GUS-SL-TEV-luc-A₅₀ mRNA (B) and was supplemented with the indicated amounts of eIF4F or eIFiso4F. eIF4A was included at a ratio of 1:70 (for eIF4F assays) or 1:30 (for eIFiso4F assays). eIF4B was included at a ratio of 1:4 (for eIF4F assays) or 1:1.6 (for eIFiso4F assays). Each mRNA construct was translated in triplicate, and the average value and standard deviation for each construct are reported. Luciferase expression is indicated as light units from 2 μl of translation lysate. (C) Degree to which the TEV IRES stimulated translation relative to the control construct.