FIG 3.

The absence of YlMhb1p leads to a decreased number of mt-nucleoids as well as a lower mtDNA copy number per cell. (A) Wild-type Po1h (WT) (top) and the Δmhb1 mutant (bottom) were stained with DAPI or DiOC₆ and were visualized by fluorescence microscopy. Cells transformed with an empty pUB4 vector or with pUB4 carrying the wild-type YlMHB1 gene were grown in YPD medium supplemented with hygromycin B (HygB). (B) PFGE analysis of mtDNA from the wild-type Po1h strain and the Δmhb1 strain. Whole-cell DNA was released from the cells in agarose blocks and was subjected to electrophoresis either without (undigested) or with prior treatment with the restriction endonuclease ApaI. Mitochondrial DNA was visualized by Southern blotting using a radioactively labeled probe derived from the ATP6 gene. EtBr, ethidium bromide-stained gel; SB, Southern blot. (C) The amount of mtDNA in the Δmhb1 mutant relative to that in the WT strain Po1h was measured by qPCR. The data presented are means of results from five independent experiments.