Figure 1.

The COX assembly defect in LSFC fibroblasts is accompanied by a decreased synthesis of several mitochondria-encoded polypeptides. Control and LSFC fibroblasts were analyzed by BN-PAGE (A) and by Western blotting (B). In A, each of the five OXPHOS complexes (Co I–V) was visualized with a subunit-specific antibody. In B, the blots were incubated with antibodies against the proteins indicated at the right of the panel. The 70-kDa subunit of complex II was used as a loading control. (C) Control and LSFC fibroblasts were pulse-labeled with [³⁵S]methionine and cysteine in the presence of anisomycin, an inhibitor of cytoplasmic protein synthesis, and subsequently were chased for 10 min (PULSE) or overnight (CHASE). Fifty micrograms of total protein were run on a 15–20% polyacrylamide gradient gel. The seven subunits of complex I (ND), one subunit of complex III (cyt b), three subunits of complex IV (COX), and two subunits of complex V (ATP) are indicated at the left of the figure. (D) Quantification of the synthesis of individual mitochondria-encoded polypeptides in fibroblasts from eight LSFC patients (four fibroblast lines in triplicate; four lines as a single experiment).