FIG. 5.

Intranuclear distribution of RNA polymerase II molecules in cells transiently expressing the Us11 gene, following the use of mAb 7C2. Formaldehyde fixation, Lowicryl embedding, and uranyl acetate staining. Bars represent 0.5 μm. (a) Gold particles are numerous over the large cluster of interchromatin granules (IG) and are markedly rare in the surrounding nucleoplasm. The nucleolus (NU) is entirely devoid of labeling, (b) Two clusters of interchromatin granules (IG) are present, only one being decorated with gold particles (IG on the right). Between these two clusters is a small focus of intermingled RNP fibrils (star) that is labeled as in Fig. 4a, b. Once again the nucleolus (NU) is unlabeled.