Tomogram of a portion of the interface between a WT IFM myotube and a closely apposed myoblast, demonstrating the coexistence of cell contacts and small fusion pores. IFMs were dissected from pupae (20 h APF) and processed as for conventional TEM (described in Materials and methods section TEM). STEM was performed on 350–400-nm-thick sections. Images were collected for every 1.5° tilt angle from 70° to −70°. Images were aligned using gold fiducial markers in IMOD. Segmentation, rendering, and 3D visualization were performed using AVIZO 3D visualization software. Transient red arrows point to examples of contact sites that were used for the 3D reconstruction. In the reconstruction, contact sites are colored green, membrane discontinuities (pores) are colored yellow, and the plasma membranes are colored pink. The display rate is 37 frames/s.
