Figure 3.

Abundance of mtDNA-Encoded rRNAs and Mitoribosomal Subunits

(A) SDS-PAGE analysis of proteins from the small (MRPS2, MRPS5, MRPS18B, and MRPS28) and large (MRPL37 and MRPL44) mitoribosomal subunits in both subjects and control cells revealed decreased steady-state levels of MRPS2 and the other mt-SSU proteins. Steady-state levels of the mt-LSU proteins are unaffected. OXPHOS complex II protein SDHA was used as a loading control.

(B) Northern blot analysis of the steady-state levels of 12S and 16S rRNA in fibroblasts from subjects and controls demonstrates that 12S rRNA, but not 16S rRNA, is decreased in fibroblasts carrying mutations in MRPS2 (S1 and S2) or MRPS22 (S3). 18S rRNA from the cytosolic ribosome was used as a loading control.