Fig. 4. Vulva cell migration defects are caused by ectopic expression of smp-1. Observations use DIC microscopy (A,B,E) and the AJM-1::GFP reporter (C,D) (see Materials and methods). (A,B) Lateral views with anterior towards the left; (C) top-down projection from a 3D confocal image. D, dorsal; P, posterior; unlabelled arrow indicates left-right depth. (D,E) Ventral views, anterior towards the left. (A,B) Animals carrying the plx-1p::SMP-1 transgene display vulva morphology defects (B) when compared with wild-type animals (A). In plx-1p::SMP-1 transgenic animals, vulva cells from each side frequently (see Table 1) fail to migrate towards the presumptive vulva midline, forming two invaginations (arrowheads in B) as seen in smp-1 and plx-1 mutants. (C) Three dimensional image reconstructions of the GFP signal from the AJM-1::GFP reporter in animals carrying the plx-1p::SMP-1 transgene (see Materials and methods) reveal vulva cells from the anterior and posterior sides that do not complete their migration to form a vulva ring (arrows). (D,E) In smp-1(ev715) animals carrying the plx-1p::SMP-1 transgene, frequent widely separated multiple invaginations are observed on both anterior and posterior sides of the presumptive vulva (arrows). Scale bars: in A, 25 µm for A-B, D-E; in C, 8 µm for C.