Figure 2.

Drok loss of function in tendon cells results in diminished Sqh phosphorylation and disturbs muscle morphogenesis. (A, A’) Drok² mutant clone of notum epithelial cells (27 hAPF) marked with CD8-GFP displays diminished levels of monophosphorylated Sqh (Sqh-P) at the apical side. (B, B’) Drok² mutant tendon cell processes and myotendinous junction display diminished levels of Sqh-P (arrows), cf. wild type tendon extension and myotendinous junction (arrowheads). (C–D’) Confocal projections of DLMs at 27 hAPF of an animal carrying a Drok² clone at the right side (D, D’). DLMs attached to wild type tendon cells display a regular anterior edge (dashed yellow line) (C’), while DLMs attached to a group of Drok² tendon cell processes display irregular anterior edge (dashed yellow line) (D’) and display detachment of the epithelia (arrow). Note that myotubes attached to Drok² tendon processes are shorter than the contra lateral muscles, cf. white guide of (C) and (D).