Figure 4.

Amine-modified nuclear matrix seen in a whole-mount electron micrograph. SAOS-2 cells were extracted with 0.5% Triton X-100 in CSK buffer, digested with PstI and HaeIII, treated with sulfo-NHS, and processed for whole-mount EM. (a) Nuclear matrices, each bounded by a nuclear lamina (L), were enmeshed in and connected to the intermediate filaments (IF) of the cytoskeleton. Within each nucleus, residual nucleoli (Nu) were connected to nuclear matrix filaments, including 10-nm branched core filaments. (b) These connections between nuclear matrix filaments and nucleoli can be seen most clearly at higher magnification and in stereo.