jeb^SH0422 mutant embryos show visceral muscle fusion defects and an absence of Fas3-positive gut structures.

R cells, target neurons and glia are normal in jeb^SH0422 eye mosaic clones.

Third larval instar animals with jeb^SH0422 clones in the eye disc show normal R cell axon targeting. Adults that contain jeb^SH0422 clones in the eye exhibit strong R cell projection defects. R8 axons frequently extend to the M6 layer, fail to enter the medulla or fasciculate with R8 axons in neighbouring columns. Analysis of jeb^SH0422 mosaics at pupal stages shows that the R cell projection errors begin in the medulla at around 55 hours APF.

jeb^SH0422 clones in lamina target neurons do not affect the projection of R cells.

The size, shape and array of lamina cartridges are irregular in adults that lack jeb function due to jeb^SH0422 clones in the eye. These lamina cartridges contain either less or more than the wild-type R cell profile. Extensions of R1-R6 axons projecting from individual ommatidia appear irregular and shortened; some R1-R6 axons appear not to defasciculate and other growth cones extend at shorter distances.