Figure 2. Three-dimensional reconstruction of two different P-bodies with surrounding ribosomes highlighted. (A and C) Image (0°) of two tilted series. Human P-body is detected by immunoelectron microscopy following Bernhard’s EDTA regressive staining, which allows easier visualization of RNA-containing structures such as ribosomes (white arrows). For the immunogold detection of P-bodies, antibodies against hDcp1a were labeled with 10 nm gold particles. Scale bar: 100 nm. (B and D) Composite images combining: the average of the 10 central digital slices of the tomogram (solid mode); the P-body (surface mode, purple) delimited by watershed segmentation after removing the density corresponding to gold particles; and 80S ribosome models (surface mode, large subunits in blue, small subunits in yellow) properly positioned in the tomogram after molecular matching. The representations are tilted for better visualization.