UAS-ogre expression in the leg prevents joint formation between tarsal segments.
Photograph of an adult leg from an animal of genotype DllGAL4 / UAS-ogre2UO15. The DllGAL4 (distalless pattern) line drives expression of ogre throughout the developing leg. Animals of this genotype consistently lack all of the tarsal joints but joints at the ends of other leg segments, such as the coxa, remain. The loss of tarsal joints is a phenotype consistent with perturbation of Notch pathway signaling. Loss of the Notch ligand Serrate from developing legs prevents the formation of tarsal joints ( Bishop et al., 1999). T – tarsus (the usual five tarsal segments appear as a single segment in the absence of joints).