Fig. 8. Expression patterns of prestalk- and prespore-specific genes in slugs derived from transformed cells (ecmAO-gal cells and D19-gal cells) and their cells. ecmAO-gal cells are shown in (A) and (C), while D19-gal cells are shown in (B) and (D). Nontreated transformed cells and their EtBr-treated cells ( cells) were separately washed twice in BSS and incubated for 16 or 28 hours on filters supported by 1.5% agar to obtain respective slugs. This was followed by histochemical staining of slug with X-gal to visualize the activity of ß-galactosidase. In slugs derived from nontreated cells, the prestalk-specific ecmAO is expressed in the anterior prestalk region (A), whereas the prespore-specific D19 is expressed in the posterior prespore region (B). In slugs derived from cells, however, the boundary between the prestalk and prespore regions becomes unclear, presumably because of incomplete sorting between the two cell types (C,D). Images of respective DAPI-stained cells at the time-point of starvation are shown in (A'-D'). The DAPI staining of cytoplasmic granules (mitochondria) is observed in nontreated Ax-2 cells (A',B'), but not in cells (C',D'). Bars, 0.4 mm (A-D); 10 µm (A'-D').