A reduced number of cells are found in the dorsal and ganglionic branches, and the dorsal trunk branches fail to fuse though, tracheal migration is generally normal in homozygous mutants and terminal cell differentiation is not affected.
Homozygous embryos have a normal somatic muscle pattern and generally hatch, although they do not develop into adult flies. Homozygous srG11 embryos that are expressing srScer\UAS.cBa under the control of Scer\GAL4en-e16E show a severe disruption of the somatic muscle pattern, especially that of the lateral transverse muscles.
sr[+]/srG11 is an enhancer of indirect flight muscle cell phenotype of ap4