Ribosome clusters at axon branch. (A and B) Ribosomes at premature branch. Red arrowhead depicts an example of ribosome density. (C and D) Ribosomes at mature branch. (E–G) Analysis of distance between ribosomes. (E) Slice of analyzed tomogram (orange triangle shows vesicle with inner membrane densities). (F) Distribution of ribosomes in the 3D volume of tomogram in E, color code by distance between ribosome particle coordinates: green <35 nm, yellow >35 nm. (G) Distance distribution of ribosome particles in tomogram E. The graph shows particles with closest neighbor distance value <40 nm (n = 178). (H) Cumulative distance distribution for all analyzed ribosomes (n = 1,614).