Fig. 2

Immunohistochemistry for UBE3A in mouse cerebral cortex following different methods of fixation. UBE3A staining in tissue fixed by perfusion (a, b). c, d Immersion fixation of mouse cortex after a delay of 15 min (similar to the fixation for our surgical material) shows only modest differences, including a subtle condensation of immunopositive cytoplasm. In both cases, UBE3A is expressed through all layers of the neocortex, with strong nuclear staining and weaker staining in somata and dendrites. UBE3A staining is nearly absent in the brain of an AS model mouse fixed by immersion after a delay of 15 min (e, f), further confirming specificity of the UBE3A antibody in brain tissue harvested under conditions similar to surgical biopsy. Scale bar = 100 μm in a, c, and e and 25 μm in b, d, and f