Most maternal cad transcripts are produced by nurse cells and are subsequently deposited in the oocyte. By the 13th zygotic cleavage CAD protein and transcript assumes a linear gradient with the highest levels found in the posterior region .
Transcripts move from anterior to posterior.
During nuclear elongation most of the transcripts move to the dorsal side, but there is some ventral localization as well. By the terminal stages of cellularization, maternal transcripts disappear and a stripe of zygotic cad accumulates in the posterior. CAD protein originating from maternal transcripts becomes localized to pole cells. In stage 12 germ-band extended embryos, cad distribution is limited to parasegment 15 and surrounds the presumptive anal pads . Subsequently, two regions of CAD staining cells appear posterior to the anal pads.