Fig. 5. Altering the SYS-1-to-POP-1 ratio also affects cell fate decisions at other A-P divisions. (A) Schematic of the C. elegans pharynx, including the location of the eight pharyngeal muscle types (labeled 1 through 8), with 3NB12 staining indicated (dark gray, no staining). (B) Embryos derived from wild type, teEx321(P_med-1gfp::sys-1) and sys-1(q544/+); teIs3(P_med-1gfp::pop-1) stained with 3NB12. Schematics to the right indicate the three pm6 and three pm7 muscle cells in the wild type and predicted cell fate changes following an anterior-to-posterior (middle) or a posterior-to-anterior (bottom) fate transformation at the division giving rise to MSa and MSp. Triangles and squares denote cells derived from the MSa and MSp lineages, respectively. (C) The E lineage. Horizontal lines indicate divisions, whereas vertical lines indicate developmental time. All divisions are anterior (left) to posterior (right), except those labeled l/r, which indicate left/right divisions. Circles, the four cells that comprise intestinal ring 1; triangles, the two cells comprising ring 9. (D) PHO-1::GFP expression in wild-type and teEx321 larvae. Arrow, posterior end of the pharynx; brackets, cells in the first two intestinal rings in wild type and the corresponding region in teEx321. Scale bar: 10 µm in B; 30 µm in D.