Figure 3.

Elements of a tomographic reconstruction of a tBid_G94E-labeled mitochondrion highlight the association of tBid with contact sites. a) Portion of the tomographic volume sliced in three perpendicular planes. Thick sections were examined by intermediate voltage electron microscopy and were used to generate reconstructions of the immunogold-labeled outer membrane. The visualization tool ANALYZE allows the tomographic volume to be rotated and resectioned along any axis, thereby revealing both internal and surface structures along with the gold labels; it also provides the ability to correlate 2-D and 3-D views of the same region or substructure. Three-dimensional perspectives allowed us to track features, such as gold particles (arrowheads), along perpendicular faces.b) Slice through the volume. Several gold particles are visible (arrowheads) in this 2 nm slice, including two closely associated with contact sites (insets; 3x magnification) The scale bar = 500 nm and applies to all panels. c) Perpendicular views of the surface-rendered volume with selected components segmented. The visualization tool SYNU allows the surface-rendered volume to be viewed in any orientation. For clarity in visualizing the contact sites (white spheres) and gold particles (yellow spheres), the outer membrane is not shown. The inner boundary membrane (IBM) is shown in dark blue and was segmented separately from individual cristae (light blue). Only four cristae are shown to demonstrate the lamellar architecture common in liver mitochondria. Where gold particles were aggregated, only one particle is shown. The IBM was made translucent in order to visualize the cristae.