Embryos expressing Cdc42^F89.Scer\UAS in the developing mesoderm under the control of Scer\GAL4^twi.PG display a weak muscle phenotype with thinner and well as fewer myotubes. Muscle seem to contain less nuclei in comparison to wild-type and exhibit attachment defects.

Expression of Cdc42^F89.Scer\UAS in border cells, driven by Scer\GAL4^slbo.2.6 does not affect the formation of the egg chamber apical cap or the migration of the border cell cluster to the oocyte.

Hemocytes in embryos expressing Cdc42^F89.Scer\UAS under the simultaneous control of both Scer\GAL4^Pxn.PS and Scer\GAL4^crq.PA show normal developmental dispersal and normal recruitment to sites of laser-induced tissue damage. However, during the migratory phase and after arrival at the wound site, the mutant hemocytes often possess several leading edges suggesting that they cannot maintain a persistent polarity.

The failure of hemocytes to maintain polarity in embryos expressing Cdc42^F89.Scer\UAS under the simultaneous control of both Scer\GAL4^Pxn.PS and Scer\GAL4^crq.PA leads them to adopt a haphazard migratory route. This defect is countered by the mutant hemocytes migrating at approximately twice the normal speed so that they reach the wound as rapidly as in wild type embryos.

Expression of Cdc42^F89.Scer\UAS under the control of Scer\GAL4^hs.2sev using heat shock results in breaks in the tracheal dorsal trunk in embryos in 9.8% of cases.

When Cdc42^F89.Scer\UAS is driven by Scer\GAL4^en-e16E in embryos at the zippering stage, just before dorsal closure, the normal extension of actin based filopodia and lamellae is not seen at the dorsal holes edge. Also the fused seam normally seen where the two zipper-fronts meet is not seen. When the opposite segmental stripes are seen to fuse, some misalignment is seen.

Cells in the wing in which Cdc42^F89.Scer\UAS is expressed under the control of Scer\GAL4^ptc-559.1 either fail to form wing hairs or form short, deformed wing hairs which have a malformed base. These cells show abnormalities in actin distribution as hair development occurs.

Causes an ectopic furrow to form at the anterior/posterior compartment boundary of the wing disc, when expressed using Scer\GAL4^ptc-559.1. Cells in the furrow (which are expressing Cdc42^F89.Scer\UAS) are shorter than normal and are bloated basally. 30% of wings derived from discs in which Cdc42^F89.Scer\UAS is expressed using Scer\GAL4^ptc-559.1 have blisters at the compartment boundary, caused by the dorsal and ventral surfaces of the wing separating. Hairs at the compartment boundary are often missing, the penetrance of this phenotype being highest proximally.