Overlapping and non-overlapping Ptch2 expression with Shh during mouse embryogenesis

In Drosophila, patched encodes a negative regulator of Hedgehog signaling. Biochemical experiments have demonstrated that vertebrate patched homologue s might function as a Sonic hedgehog (Shh) receptor. In mice, two patched h omologues, Ptch and Ptch2, have been identified. Sequence comparison have s uggested that they might possess distinct properties in Shh signaling. In t he developing tooth, hair and whisker, Shh and Ptch2 are co-expressed in th e epithelium while Ptch is strongly expressed in the mesenchymal cells. We report here the chromosomal localization of Ptch2 and further analysis of P tch2 expression. Throughout mouse development, the level of Ptch2 expressio n is significantly lower than that of Ptch. In early mouse embryos, Ptch an d Ptch2 were found to be co-expressed in regions adjacent to Shh-expressing cells in the developing CNS. Similar to other epidermal structures, Shh an d Ptch2 also show overlapping expression in the developing nasal gland and eyelids. Thus, during mouse development, Ptch2 is expressed in both Shh-pro ducing and -nonproducing cells. (C) 1998 Elsevier Science Ireland Ltd. All rights reserved.