Figure 7.

ESI mapping of RNA within the IGC. A mouse 10T½ fibroblast cell nucleus was imaged at 120 eV, and 155-eV energy loss images were collected and used to obtain a net phosphorus image (Net P). Signal in the net phosphorus image is shown as white on black, whereas the 120- and 155-eV images are shown as black on white. The large arrows indicate the positions of interchromatin granule-sized particles within the IGC. The small arrows indicate the position of considerably smaller particles within the IGC that contain significant quantities of phosphorus. Bar, 50 nm.