Next, we performed cytoplasmic transfer of the T15091C mtDNA from P29-95 cells into r0 B82 cells (see Materials and Method) to exclude the possibility that the repeated recloning processes used
to isolate P29-95 cells (Fig. 1B) preferentially selected cells with nuclear abnormalities that induce respiration defects. In the case of nuclear abnormalities, respiration defects would not be transferred to r0 B82 cells along with the transfer of the T15091C mtDNA from P29-95 cells. Thus, we performed intercellular transfer of T15091C mtDNA by fusion of enucleated P29-95 cells with r0 B82 cells.