Mitochondrial DNA deletion occurs in mitophagy-deficient strains during nitrogen starvation.
A, large and small colonies formed after 10 days of starvation were inoculated onto YPD, YPL, and YPEG plates and grown for 2–3 days at 30 °C. atg32Δ and atg11Δ small colony-derived cells only were unable to grow on YPL or YPEG. B, large and small colonies formed after 6 or 10 days starvation were cultured in YPD to mid-log phase (lanes 1–5 and 8–11, 6 days in SD-N; lanes 6, 7, 12, and 13, 10 days in SD-N). Cell lysates were immunoblotted with anti-Cox2, anti-Por1, and anti-Pgk1 (loading control) antibodies. atg32Δ and atg11Δ small colony-derived cells only did not produce the mitochondrially encoded protein Cox2. C, large and small colonies formed after 5 or 6 days starvation were cultured in YPD to mid-log phase. Whole cell DNA was digested by BamHI or ScaI and analyzed by Southern blotting with COX1 and COB mtDNA probes. The atg32Δ and atg11Δ small colonies showed absent or aberrant COX1 and/or COB bands. WT, wild-type.