Summary

inmesenchyme—to prevent diastema tooth formation. tracheal branching in Drosophila. FGF signaling induces We provide genetic evidence that they function to ensure that diastema tooth buds are refractory to signaling via FGF ligands that are present in the region and thus prevent these buds from engaging in the D. spry expression, and via this effect, the FGF pathway limits the range of its own signaling activity (Hacohen et al., 1998). Subsequent experiments showed that D. spry also regulates epidermal growth factor (EGF) re-ceptor and other receptor tyrosine kinase (RTK) signal-ing pathways (Casci et al., 1999; Kramer et al., 1999