Figure 5.

The effects of viral protease-mediated cleavage of eIF4G on the efficiency of viral IRESes to direct translation in ribosome-depleted RRL. Ribosome-depleted RRL translation reactions containing physiological concentrations of added KCl and MgCl₂ (see legend to Fig. 2), were pre-treated with Lb protease in H100 buffer (10 µg/ml final concentration; +Lb panel) or H100 buffer for 15 min at 30°C (–Lb panel). Following inactivation of protease with E-64, reactions were programmed with the indicated forms of pOp24- or pIRESp24-derived mRNAs (final RNA concentrations 6.6, 3.3 and 1.65 µg/ml for Op24 mRNAs and 10, 5 and 2.5 µg/ml for IRESp24 mRNAs). Translation products were analysed as described in the legend to Figure 2.