(A, B) Merged time lapse video imaging the localization of murine leukemia virus (MLV) Gag (red) relative to locations of cell–cell contact (green). Cells expressed (A) wild-type MLV Env or (B) MLV Env Δ16 C-terminal amino acids (image adapted from Jin et al.73). (C, E, G) Secondary electron images illustrating the topology of the cell surface. (D, F, H) Backscatter images illustrating the distribution of the MLV Env on the cell surface. (E–H) Express late domain defective HIV-1 Gag; (C–F) express wild-type MLV Env; (G, H) express MLV Env Δ33 C-terminal amino acids. (C–H) Scale bars 200 nm.