Fig. 5. RNAi-mediated reduction of MTP18 results in mitochondrial fusion. Two examples of specific RNAi-mediated protein reduction is shown on western blots with extracts from HeLa cells transiently transfected with shRNA-expressing plasmids (as indicated) to target MTP18, Mfn1, Drp1 and p110; hFis1 served as loading control. (B) Representative confocal images of HeLa cells (right panels, higher magnification) transiently transfected with indicated shRNA-expressing vectors labelled with anti-Hsp60 and treatment with nocodazole before staining to reveal mitochondrial morphology. Bars, 20 µm. Diagrams show the percentage of transiently transfected HeLa cells (corresponding to the cell shown on the left) with indicated mitochondrial morphology (Fu, highly fused mitochondria; Nw, filamentous mitochondrial network; Fi, highly fragmented mitochondria). The majority of cells that show highly fused mitochondria were found in cells expressing shRNA against MTP18 and Drp1. Fragmented mitochondria were found in cells expressing shRNA against Mfn1. No obvious mitochondrial phenotype was found in cells expressing p110-shRNA.