Fig. 1. Electron micrographs of amoebae, fixed 30 minutes after microinjection, showing the distribution of colloidal gold particles coated with either wild-type NTF2 (A) or W7A mutant NTF2 (B). There was significantly less binding of the mutant NTF2-gold to the nuclear pores (arrows). Since the mutation inhibits binding to FxFG repeats, the results suggest that these moieties are present in the pore complexes. The structures (nl) seen extending from the inner surface of the envelope are components of the nuclear lamina. In A. proteus, the lamina forms an elaborate honeycomb-like supporting structure. c, cytoplasm; n, nucleus. Bar, 100 nm.