Figure 1.

Defect in COX I Translation and Normal Levels of Mitochondrial mRNAs in Subject Fibroblasts

(A) Pulse-labeled mitochondrial polypeptides were chased for 10 min (PULSE) or overnight (CHASE). 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.

(B) Northern blot analysis of fibroblasts from the subject, TACO1 patient, and controls. Ten micrograms of total RNA was separated on a denaturing formaldehyde agarose gel (MOPS buffer) and transferred to a nylon membrane. We labeled the PCR products (300–500 bp) of individual mitochondrial genes (COX I, COX II, COX III, ND 1, 12S, and 16S) with [α-³²P]-dCTP by using the MegaPrime DNA labeling kit (GE Healthcare). The 12S and 16S mitochondrial rRNAs and actin were used as loading controls.