Rok-CAT overexpression in LECs at 25°C, ‘weak’ phenotype. F-actin labelled with GMA-GFP. Beginning of morphogenesis, migration and constriction visible. Constricting LECs show high levels of cortical actin (blue arrowheads). LECs migrate, showing lamellipodia (cyan arrowheads) and blebbing (pink arrowheads). Some LECs show pulsatile behaviour (red dot). Scale bar, 10 μm; a, anterior; p, posterior; m, medial (corresponds to dorsal); l, lateral (corresponds to ventral).