Extended Data Fig. 2: Visualization of the five selected genes in expressing and not expressing cells.

a, The Tg gene is expressed in thyrocytes where both alleles form prominent TLs expanding into the nuclear interior. In neighboring cells with a silent Tg gene - parathyroid gland cells, tracheal chondrocytes, epithelial cells, fibroblasts and muscles - Tg is highly condensed and sequestered to the nuclear periphery. b, The Ttn gene is expressed in skeletal muscle (b1), heart muscle (b2) and myotubes differentiated from Pmi28 myoblasts in vitro (b3). Note that only muscle nuclei (solid arrowheads) exhibit TLs. In muscle fibroblasts (arrows) or undifferentiated cultured myoblasts (empty arrowheads), Ttn is condensed at the nuclear periphery. c, The Neb gene is expressed in skeletal muscles and cultured myotubes, although to a lesser degree than Ttn. Accordingly, it forms smaller TLs. Arrowheads indicate muscle nuclei; arrows indicate fibroblast nuclei with silent Neb. d, e, The Myh11 (d) and Cald1 (e) genes are expressed in smooth muscles of colon and bladder where they form TLs. Note that after RNA-FISH, only smooth muscles (arrowheads) but not the neighboring epithelial cells (arrows) exhibit TLs. In addition, Cald1 is expressed in cultured myoblasts and forms small TLs in these cells. As indicated above the panels, images display signals after either RNA-FISH (no tissue/cell DNA denaturation and no RNasing), or simultaneous detection of DNA and RNA (tissue/cell DNA denaturation but no RNasing). All images are projections of 1–3 µm confocal stacks. Scale bars for overviews of skeletal muscle, colon and bladder, 50 µm; for the rest of the panels, 5 µm. Data represent 100 in a,b3 and 10 in b1,b2,c-e independent experiments.