Figure 2.
Transmission electron micrographs of purified nucleoli. The nucleolar fraction was obtained from HeLa cells, as described in MATERIALS AND METHODS and submitted to electron microscopy analyses (A) Nucleoloar fraction at 4000× magnification. Nucleoli are the main structures observed in the last fraction of the cellular fractionation procedure. (B) Nucleolar fraction at 20,000× magnification. Purified nucleoli have conserved their characteristic ultrastructure in three main compartments: FC, fibrillar center; DFC, dense fibrillar component; and GC, granular component.