Mitochondrial retention defects of fragmented mitochondria. (A) 10-fold serial dilutions of cells carrying a plasmid expressing Myo2-Fis1 from a tetO promoter (+) or a vector control (−) were spotted on glucose-containing selective medium with (off) or without (on) doxycycline and incubated at 30°C. (B) Cells carrying a vector control (ctrl) or a plasmid expressing Myo2-Fis1 from a GAL promoter were grown in galactose-containing synthetic complete medium supplemented with 0.5% glucose and analyzed as in Fig. 4 A. Bar, 5 µm. (C) Cells prepared as in B were scored for mother cells completely lacking mitochondria. (D) FZO1 WT cells, Δfzo1, and Δfzo1 Δdnm1 cells containing a plasmid carrying WT FZO1 and a URA3 marker received as a second plasmid either an empty vector (−) or plasmids overexpressing YPT11 (+) or ypt11(G40D) from a GPD promoter. Strains were first allowed to lose the FZO1 plasmid in selective medium containing uracil. Then, 10-fold serial dilutions were spotted on glucose-containing selective medium with or without 5′-FOA, which counterselects against cells that have maintained the FZO1 plasmid. Data pooling and statistics are detailed in Table S4.