Effect of constitutive activation of actomyosin with N-Rok::dGBP1 in the kni domain on cell intercalation. (a) Confocal projections showing lateral views of fixed sqh_Sqh::GFP kniGal4 control and sqh_Sqh::GFP kniGal4 Rok::dGBP1 embryos stained for DE-Cad (red) and vermiform (blue). Note the presence of ectopic Sqh::GFP foci in the embryos expressing the engineered kinase (arrowheads). The bottom panel shows the magnification of a single branch from the respective image of stage 16 embryos to show the characteristic pattern of lines and small rings of AJs, corresponding to auto- and intercellular AJs, respectively. Yellow arrows point to the rings corresponding to intercellular AJs. (b) Stills from time-lapse movies showing projections of dorsal branches of sqh_Sqh::GFP kniGal4 control embryos and sqh_Sqh::GFP kniGal4 Rok::dGBP1 embryos; α-Cat::mCherry (magenta) marks cell junctions. In the course of the experiments with UAS α-Cat::mCherry stock, we noticed background expression of α-Cat::mCherry in the epidermis, regardless of the driver used, and even in the absence of a driver. However, we verified a robust signal increase with the use of enGal4 driver. Therefore, the observed background of α-Cat::mCherry expression, although limiting a clearer view of the imaged embryos (especially at the beginning of branch emerging), did not prevent the use of this line for studying intercalation in dorsal branches via live imaging. Scale bars, 10 or 5 μm on the magnification panel.