Mitochondrial aggregation induced by co-expression of Green Fluorescent Protein(GFP)and an antiapoptotic factor Bcl-xL. HeLa cells were co-transfected with cDNA of Bcl-xL and empty control vector(A and B)or GFP(C, D and E). The cells were double-stained with antibody against Bcl-xL(A and C)and a mitochondria specific fluorescent dye, MitoTracker Red(B, D and E). E: Higher-magnification of aggregated mitochondria. Note that green fluorescence in D and E is derived from GFP and that the aggregated mitochondria were gathered but not fused(E). Scale bars, 20 μm(A~D)and 10 μm(E). (Pictures were modified from those that were published in Biochemical and Biophysical Research Communications 314, 711― 716(2004). Aokage et al.).