shot^SF20 homozygous embryos show efficient dorsal closure, but with abnormal dynamics (i.e. a smaller dorsal hole width during dorsal closure, shown by a significant increase in the length:width ratio, and severe decrease in the fractional contribution of zippering, despite of an insignificant change in epithelial sheet translocation), as compared to controls. The dorsal-most epithelial cells of these mutants, which do not present significant changes in cell size, exhibit a slightly disorganized microtubule network (i.e. frequent abnormally long, bent and protruding microtubules at the leading edge; an increased instability of the dynamic pool of microtubules, as shown by a significant decrease in the halftime, but not in the mobile fraction, of tubulin in FRAP experiments, and by the significant increase in the growth rate, but not in the lifetime, of growing microtubules; but insignificant changes in overall microtubule directionality), and exhibit a significant decrease in the number of normal-sized filopodia and frequent long apical protrusions at the leading edge, as compared to controls.

The growth cones of shot^SF20/Df(2R)MK1 primary embryonic neurons in culture show a high frequency of transverse abaxial microtubule polymerisation (19.1% of polymerisation deviates more than 45[o] from the axon axis) compared to wild-type neurons (6.7%). The axons of the neurons are reduced in length compared to wild-type controls.

shot^SF20/Df(2R)MK1 primary neuronal cultures show a significantly reduced axonal length compared to controls. They also show an increase of neurons with unbundled microtubules - these microtubules display irregular trajectories and frequent loops in axons and growth cones.

shot³/Df(2R)MK1 primary neuronal cultures show a significant reduction in filopodia number.

shot^SF20/Df(2R)MK1 mutants show strong reduction of output synapses at the NMJ, while this phenotype is not seen in the CNS.

Homozygous and hemizygous embryos show a paralytic phenotype. Neuromuscular junctions occupy far less surface of their respective muscles, their branches are reduced in length and boutons appear reduced in number and size in homozygous, hemizygous, shot^SF20/shot^91k and shot^SF20/shot^el3 embryos compared to wild-type. Typical presynaptic specialisations, such as T-bars, are missing in some cases in homozygous embryos. shot^SF20/shot^el3 neuromuscular junctions have excitatory junctional currents, indicating that neuromuscular transmission occurs. Peripheral nerves can form correctly in hemizygous and shot^SF20/shot^el3 embryos. The short SNb-branch has a tendency to stall in hemizygous embryos. The ipsilateral local arborisations of the RP3 neuron are almost normal, but the contralateral arborisations of the RP3 neuron are severely reduced and often form swellings or blobs in shot^SF20/shot^el3 or shot^SF20/shot^91k embryos. shot^SF20/shot^el3 embryos do not show any obvious defects in muscle patterning at stage 16. However, at stage 17, severe detachment of the muscles from the cuticle is seen, although the muscles remain attached to each other. The thick dendrites appear collapsed and the cilia frequently appear detached from the tip of the capsule in shot^SF20/shot^el3 or shot^SF20/shot^91k scolopidial sensory organs.

shot^SF20/shot[+] is a suppressor | partially of visible | adult stage phenotype of Scer\GAL4^A9, Shrm^A.UAS

shot^SF20/shot[+] is a suppressor | partially of decreased size | adult stage phenotype of Scer\GAL4^A9, Shrm^A.UAS

kra², shot^SF20/shot[+] has neuron phenotype

kra², shot^SF20/shot[+] has filopodium phenotype