Figure 1.

Representative electron micrographs of control and AP180-depleted synapses. Arrowheads in the enlarged insets illustrate tubular structures occasionally found in AP180-depleted nerve terminals. Such structures were not normally seen in synapses from control neurons. Morphology and SV density were unchanged but SVs appeared slightly larger and more heterogeneous in synapses depleted with AP180.¹² Hippocampal neurons were cotransfected with AP180 sIRNA and an eGFP-encoding plasmid. Six to eight days after transfection neurons were fixed with 4% paraformaldehyde before permeabilization by freeze-cracking in liquid nitrogen. Samples were labeled with anti-GFP antibody and NANOGOLD^® particles, post-fixed with 2% glutaraldehyde, gold-enhanced and processed for electron microscopy. Images were taken using Zeiss 910 electron microscope. Neurites and terminals of control or KD neurons were identified by absence/presence of intense immunogold labeling scattered in the cytoplasm. Scale bar, 500 nm; 200 nm for the inset; KD, knockdown.