FIG 3.

Lack of HPM1 results in deficiencies in large-subunit biogenesis and translation initiation. (A) Polysome profile analyses of WT and hpm1Δ mutant cells were done as described in Materials and Methods. Shown are two independent profiles each of the WT and of the hpm1Δ mutant. (B) Polysome profile analysis of cold-stressed (15°C) cells was done as described for panel A. (C) Total subunit analysis of WT and hpm1Δ mutant cells was done as described for panel A, except that cells were not pretreated with cycloheximide, the lysis buffer was replaced with buffer C, and 2 A₂₆₀ units of extract was loaded. (D) Quantification of ratios of large to small ribosomal subunits for both the polysome profiles (A) and total subunits (C). Peak areas were determined with Graphical Analysis 3.8.4 software. Error bars represent standard deviations of four independent experiments. Unpaired t test two-tailed P values for the differences in the subunit ratios were 0.004 for the polysome ratio and 0.057 for the dissociated subunit ratio.