Fig. 2. The plx-1::gfp transcriptional reporter and the plx-1p::PLX-1::GFP translational reporter are expressed during vulva morphogenesis. In wild type (A-F), expression is predominant in P5.p and P7.p descendants and the reporters are widely expressed in most cells undergoing ring formation. The signal increases during later phases of ring formation. (A,C) Transcriptional reporter. (B,D) Translational reporter. The GFP signal of the plx-1p::PLX-1::GFP translational reporter is first (B) distributed on the whole cell membrane of early expressing cells and highlights filopodia-like extensions but later (D) begins to concentrate at the cell surface zone contacting neighboring cells (arrowheads). As vulva morphogenesis progresses (E,F), the PLX-1::GFP signal is widely expressed at the cell membrane of ring forming cells (arrowheads). The PLX-1::GFP signal is localized predominantly on the lumen side of vulva ring forming cells of wild-type animals (arrows in E,F). In smp-1(ev715) mutants (G,H), vulval cells that do not display a migration phenotype show the same pattern of expression as wild type. By contrast, cells displaying an aberrant migration phenotype in smp-1(ev715) and unc-73(rh40) mutants (arrowheads in I-L) often lose the predominant localization of the PLX-1::GFP signal at the lumen-facing membrane. F,H,J,L are DIC microscopic images of E,G,I,K, respectively. (M) Fluorescence confocal 3D microscopy revealed the PLX-1::GFP signal highlighting the lumen-facing surface of crescent-shaped cells forming vulva rings (M is a 3D confocal projection, N is a sketch of the staining in M with PLX-1 highlighted in green). The signal is maintained for a while in the vulva cells that have completed their migration and formed a ring (white arrows in M). However, as externally positioned cells are recruited to initiate their migration towards the presumptive vulva midline, the PLX-1::GFP signal becomes concentrated in cell surface membrane that is just entering the vulva proper (red arrow in M). D, dorsal; P, posterior; unlabelled arrow indicates left-right depth. Scale bars: 25 µm in A-L; 1.8 µm in M.