In embryos, expressing Gef26dsRNA.Scer\UAS under the control of Scer\GAL4srp in macrophages, the macrophages do not populate the posterior nervous system at stage 14 and leave a gap which is not entirely closed later. The macrophages become trapped between the yolk and amnioserosa.
Transcription from the P{UAS-dizzy.ds} construct should produce Gef26 dsRNA, resulting in dsRNA interference (RNAi) of the Gef26 gene.