Western blots (upper) and quantification (lower) of Tfam distribution in the mitochondria and cytosolic fractions at days 0, 2 and 4 days of differentiation. Tfam protein level was significantly higher in the cytoplasm (*P<0.05) at day 0 and then tended to decrease in cytoplasm and increase in the mitochondria fraction at days 2 and 4 of differentiation. VDAC and GAPDH are representative mitochondrial and cytosolic proteins respectively.