Fig. 4. VAB-19 localizes to epidermal attachment structures. (A-I) VAB-19::GFP progressively co-localizes with intermediate filaments. Confocal images of VAB-19::GFP expression (juIs167) visualized using anti-GFP immunostaining (green); intermediate filaments were visualized using the MH4 monoclonal antibody (red). At the comma stage (A-C), VAB-19::GFP partly colocalized with intermediate filaments. At the intermediate elongation stage (D-F), VAB-19::GFP and intermediate filaments both localized to muscle-adjacent regions of the dorsal and ventral epidermis. During later embryogenesis and larval stages until adulthood, staining of anti-GFP and MH4 was coincident. (G-I) L1 stage epidermis in z-axis section. (J-L) Lateral view of adult epidermis. (M-R) Colocalization of VAB-19::GFP and Myotactin (MH46 antigen). At the intermediate elongation stage (M-O), VAB-19::GFP and Myotactin are both localized to epidermal cell regions adjacent to muscle. In adults (P-R), the bands of Myotactin and VAB-19::GFP are interrupted by gaps corresponding to the positions of neuronal processes (arrows), at which positions MH4 staining is usually enhanced (K, arrow). Like Myotactin, but unlike MH4 staining, VAB-19::GFP is absent from such process gaps (compare J and P). VAB-19::GFP was also expressed in pharyngeal marginal cells (S); unlike Myotactin (T), VAB-19::GFP was localized throughout the apical basal axis of these cells and was more concentrated at the apical and basal surfaces. Scale bars: 5 µm (G-I); 10 µm (all others).