Figure 7.

Addition of p50 (central one-third) or p100 (C-terminal two-thirds) fragments of eIF4G strongly promotes reinitiation on uncapped TPI/ter mRNAs, but not on mRNAs with the CSFV, CrPV, or EMCV IRESs. (A) Uncapped TPI/norm, TPI/2ter, TPI/+8norm, and TPI/2+8ter mRNAs, as indicated, were each translated at 15 μg/mL with 100 mM added KCl, in the absence or presence of 100 nM p100, or 200 nM p50. (B) Uncapped mRNAs as designated were translated at 20 μg/mL (TPI), 15 μg/mL (EMCV), 60 μg/mL (CSFV), or 25 μg/mL (CrPV). Added KCl was 100 mM (135 mM for CrPV/mRNAs), and translation was carried out in the presence or absence of 100 nM p100, or 200 nM p50. Reinitiation efficiency was calculated as in Fig. 2, and is given (as %) below each lane of the assays in which quantifiable reinitiation occurred.