Figure 3.

Mitoribosome particles are assembled and more abundant in mS38-depleted mitochondria. See also Supplementary Figure S3. (A–C) Sucrose gradient sedimentation analyses of mitoribosomal protein markers on mitochondrial extracts prepared from the indicated strains carrying intronless mtDNA (I⁰) in the presence of 0.8% digitonin and the conditions stated including either EDTA (A and C) or Mg²⁺ (B). Extracts from a ΔmS38 strain expressing mS38-GST from an integrative plasmid were prepared in the presence or absence of a high concentration of RNAse (600U) to disrupt mitoribosome integrity. (D) To compare the levels of mtSSU (S), mtLSU (L) or monosome (M) in the WT and ΔmS38 strains, the indicated fractions from the sucrose gradients in panel (B), were pooled and equal volumes analyzed by SDS-PAGE and immunoblotting. (E) Steady-state levels of mitoribosomal proteins estimated by immunoblot analyses. Porin was used as a loading control.