FIGURE 2.

Polysome profiles and 40 S/60 S subunit abundance ratio (insets) of the isolated 18 S rRNA mutants. Left columns for each panel are as follows: A₂₅₄ profiles of cell extracts prepared from wild-type and mutant yeasts (NOY908 derivatives in Table 1) that had been grown in the rich YPD medium at indicated temperatures for 3 h are shown with the P/M ratio and doubling time of the strains used (n = 2–4) (see “Materials and Methods”). Lines indicate the locations of free 40 S and 60 S subunits, monosomes (M), and polysomes with indicated number of ribosomes. Right columns, insets show A₂₅₄ profile of total ribosomes dissociated into two subunits by the absence of Mg²⁺. Numbers below indicate the mass ratio of 60 S to 40 S subunit, with bars indicating S.D. (n = 2–3). The original A₂₅₄ profiles were traced by the autotrace function of the Canvas^TM software.