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

Abstract

In Drosophila, patched encodes a negative regulator of Hedgehog signaling. Biochemical experiments have demonstrated that vertebrate patched homologues might function as a Sonic hedgehog (Shh) receptor. In mice, two patched homologues, Ptch and Ptch2, have been identified. Sequence comparison have suggested that they might possess distinct properties in Shh signaling. In the developing tooth, hair and whisker, Shh and Ptch2 are co-expressed in the epithelium while Ptch is strongly expressed in the mesenchymal cells. We report here the chromosomal localization of Ptch2 and further analysis of Ptch2 expression. Throughout mouse development, the level of Ptch2 expression is significantly lower than that of Ptch. In early mouse embryos, Ptch and Ptch2 were found to be co-expressed in regions adjacent to Shh-expressing cells in the developing CNS. Similar to other epidermal structures, Shh and Ptch2 also show overlapping expression in the developing nasal gland and eyelids. Thus, during mouse development, Ptch2 is expressed in both Shh-producing and -nonproducing cells.

Essential role for ligand-dependent feedback antagonism of vertebrate hedgehog signaling by PTCH1, PTCH2 and HHIP1 during neural patterning

“…The Ptch2 (−0.5kb) enhancer displays a ventral distribution throughout the entire CNS, consistent with Ptch2 as a direct readout of SHH signaling (Fig. 1C,D) and in line with previous reports of Ptch2 expression in the neural tube (Motoyama et al, 1998a). To examine PTCH2-mediated antagonism of HH signaling, and to compare PTCH2 directly with other cell surface HH pathway antagonists, we expressed PTCH2, PTCH1 and HHIP1 in HHresponsive NIH/3T3 fibroblasts.…”

The Glandular Stem/Progenitor Cell Niche in Airway Development and Repair

“…Similarly, Indian Hedgehog (Ihh) and sonic Hedgehog (Shh) are required for the polarization of mammary glandular ducts, and mammary glands deficient for the Hedgehog signaling mediator Gli2 display glandular duct abnormalities (44). Expression of mRNAs for Shh, the Hedgehog intracellular regulator Gli1, and the Hedgehog receptor Ptch has also been detected in the mouse nasal gland and regenerating airway epithelium, suggesting that Hedgehog signaling may be important for glandular function as well for airway regeneration (45)(46)(47). Of the molecular markers present in SMGs, Lef-1, Shh, and Ptch appear to be the most specifically linked to bud formation of these organs.…”

The hedgehog signalling pathway in tumorigenesis and development

“…It has been proposed that the response of target tissues to hedgehog is dependent on the detection of intracellular sterol levels by the sterol sensing domain (Cooper et al, 1998). Recently a second patched gene was identi®ed in vertebrates, and while it appears to act in a similar manner to patched in vitro, its role in hedgehog signalling remains to be elucidated (Carpenter et al, 1998;Motoyama et al, 1998;Smyth et al, 1999;Takabatake et al, 1997).…”