CONTRASTING DISTRIBUTIONS OF PATCHED AND HEDGEHOG PROTEINS IN THE DROSOPHILA-EMBRYO

The segment polarity genes patched (ptc) and hedgehog (hh) are thought to encode a receptor and signal molecule respectively, components of a signal transduction pathway that regulates the transcription of the wingless gene in the Drosophila embryo. Here we describe the productio n of antibodies specific for the products of these two genes and the p atterns of protein distribution that they reveal in the developing emb ryo. The results are consistent with the hh protein being secreted by cells in which it is expressed and support a role for ptc in the recep tion of the putative hh encoded signal.