Fig. 5. Electron microscopy reveals that ADAR2 localizes in a novel subnucleolar compartment. Ultrathin sections from rat brain neurons were immunogold labeled with antibodies directed against ADAR2 and fibrillarin. The ADAR2-specific gold particles decorate the periphery of the fibrillar component (f) and are largely excluded from the fibrillar centers (fc) and the granular component (g). By contrast, the anti-fibrillarin antibody produces an intense labeling of the dense fibrillar component. Bar, 300 nm.