Fig. 9. Char is localised at the inner nuclear membrane. (A,B) Localisation of Char (red) and Lamin (green) in the NE of embryos viewed in sagittal sections (A) and from the top (B). (C,D) WGA (green) and Char (red) localisation at the NE of embryos viewed from the top (C-C'') and in sagittal sections (D,D'). C shows a detail of C' and D' a detail of D. Scale bars: 5 µm, except in C,D' (300 nm). (E-H) Immunogold localisation of HA-Char (black arrows) in an early embryo. The nucleoplasm (N) and cytoplasm (C) of three different cells are indicated and have very different electron density. The white arrows indicate contacting cell surfaces. HA-Char is concentrated at the NE. High magnification views of representative localisation at the NE are shown in F, where the white line defines the position of the NE. (G) Representative localisation of Lamin. (H) Quantification of the localisation of HA-Char and Lamin. We positioned the NE at the boundary between the nucleoplasm and cytoplasm (white lines in F and G show examples) and determined the localisation of gold particles (15 nm) at the boundary, or the inner (in) or outer (out) side of the NE. Lamin and HA-Char are distributed similarly, and are particularly biased towards the inner side of the NE. (I,J) S2 cells stained with Char (green), Lamin (red), Hoechst (blue) and Phalloidin (white) to mark F-actin at the cell cortex after permeabilisation with Triton (I) or digitonin (J). Char staining is absent from the NE when the plasma membrane but not the NE is permeabilised (with digitonin).