FIGURE 6.

The 7-repeats and NTD are required, but the RRM is dispensable, for WT translation initiation in vivo. (A–F) Polysome profiles of tif3Δ mutants. Strains from Figure 5 were grown in SC-Leu at 30°C to an A₆₀₀ of ∼1, with cycloheximide added prior to harvesting. WCEs were separated by SDGC and scanned at 254 nm. Mean polysome/monosome ratios (P/M) and SEM from multiple replicates are given. (G) Polysome profiles were determined for the indicated strains as in A–F. The mean P/M ratio for the vector transformants was subtracted from the mean P/M ratios for mutant or sc WT transformants, and the resulting values were normalized to that obtained for sc WT to yield Tif3-dependent P/M ratios. Protein levels and complementation ability (comp’n) from Figure 5 are included for comparison.