FIGURE 5.

Deregulated assembly of Yfh1 causes Aco1 sequestration and loss of mitochondrial DNA integrity. A, yeast cultures were performed as in Fig. 4G except that 100 μm FeCl₃ was added during growth at 37 °C. The data points are the averages of two independent growth curves. B and C, equal numbers of cells from the cultures described above, after 24 h (B) or 2, 6, and 24 h (C) of growth, were plated and scored for viability (B) or respiratory capacity (C) as in Fig. 4 (I and J). The data show the means ± standard deviation of four (WT and Y73A*) or two (WT* and T118A/V120A*) independent experiments, with two plates per experiment scored for each strain analyzed. ‡, p ≤ 0.02. D–F, cultures were performed as above, and mitochondria were isolated. T, S, and P fractions were prepared and analyzed as in Fig. 4. In D only, the amounts of T, S, and P fractions analyzed for WT* and Y73A* were 5- and 2.5-fold lower, respectively, than those analyzed for WT. The membrane analyzed in B and C was probed sequentially with antibodies against Aco1 and Nfs1.