DWnt-4 and Wingless have distinct activities in the Drosophila dorsal epidermis

Wnt genes are often expressed in overlapping patterns, where they affect a wide array of developmental processes. To address the way in which various Wnt signals elicit distinct effects we compared the activities of two Wnt genes in Drosophila, DWnt-4, and wingless. We show that these Wnt signals produce distinct responses in cells of the dorsal embryonic epidermis. Whereas wingless acts independently of hedgehog signaling in these cells, we show that DWnt-4 requires Hh to elicit its effects. We also show that expression of Wg signal transduction components does not mimic expression of DWnt-4, suggesting that DWnt-4 signaling proceeds through a distinct pathway. The dorsal epidermis may therefore be useful in the identification of novel Wnt signaling components.