Figure 7. miniSOG-tagged RIβ localizes RIβ to the mitochondria and to the nucleus using electron microscopy.
Primary hippocampal or cortical cells were electrophorated with miniSOG-tagged RIβ. Mersalyl acid was used in the blocking step to reduce background nonspecific labeling of mitochondria. The differential contrast generated between (A) a non-transfected nucleus and (B) a transfected nucleus following photooxidation is evident. RIβ is localized to the nucleus and nuclear envelope. The differential contrast generated between (C) a non-transfected photo-oxidized mitochondrion and (D) a transfected photo-oxidized mitochondrion is evident. The well-preserved mitochondrion allows detection of RIβ at the mitochondrial cristae and the inner membrane. 126 transfected darkened mitochondria and 71 non-transfected light mitochondria were counted. Representative images for (C) non-transfected and (D) transfected mitochondria are shown.