Fig. 1. unc-53 sex muscle phenotypes. (A,B) Male sex muscles; lateral view. (A) Wild type with a pAB::GFP reporter revealing the diagonal muscles. (B) In the unc-53(e2432) mutant, which is stained with phalloidin-FITC, one diagonal muscle is shorter than normal and is attached in a dorsal position (arrow); the spicule retractor muscles are also abnormally short (arrowhead). (C-F) Hermaphrodite sex muscles. (C,D) Lateral view of wild-type (C) or unc-53 (D) vulval muscles (vms) with phalloidin-FITC staining. The distance between the anterior and posterior vm1 cells is reduced in the mutant as indicated by the double-headed arrows. (E) A schematic ventral view of the wild-type vulval muscles, bodywall cells are in red, seam cells in blue. The feet-like structures extending from the base of the four vm1 and four vm2 muscles are shown (arrowhead). (F) Ventral view of the four vm1 in unc-53(n152) revealed with a pAB::GFP reporter. No feet-like structures are visible, and the vm do not attach at their normal position. (G,H) Ventral view of the sex myoblasts during their division and migration in the wild-type (G) and unc-53(n152) (H) worms. Top, idealised schema; bottom, fluorescent images of worms expressing the pAB::GFP reporter. In the mutant, no longitudinal migration is observed and the distance (indicated by the arrows) between the anterior and posterior set of sex myoblasts is eliminated; they are all grouped around the future vulva (dotted circle) in the mutant. The bright round cells are motoneurones (m) in a higher plane of focus. Scale bars: 10 µm.