PKD1 and cyst: Consistent with the results for cyst-derived cells harboring a homozygous PKD1 mutation, the mtDNA copy number (Fig. 6B) and PGC-1α protein and mRNA expression (Fig. 6C and D) in WT 9-7 were also lower than those observed in RCTEC-LTA, and mitochondria from WT 9-7 further showed more fragmented shapes than those from RCTEC-LTA (Fig. 6E).