Fig. 5. Ultrastructural analysis. Nuclear formation was performed as before with cytosol and light membranes. Reactions were run with mock-treated membranes along with either buffer (control) or in the presence of 100 µM -SNAP. Shown are results for -SNAP_L294A that were identical to -SNAP_wt (data not shown). In parallel, a reaction was performed with membranes pretreated with NEM, but without exogenous -SNAP (NEM). Samples were fixed, processed and imaged by transmission electron microscopy. Note the flattened cisternae and nuclear pores (arrowheads) in control reactions and the tight attachment of vesicles (arrows) upon inhibition with -SNAP, but not with NEM. Bars, 500 nm.