Expression of the mouse Gli and Ptc genes is adjacent to embryonic sources of hedgehog signals suggesting a conservation of pathways between flies and mice

The three mouse Gli genes are putative transcription factors which are the homologs of cubitus interruptus (ci) in Drosophila. Along with the gene patched (Ptc), ci has been implicated in the hedgehog (Hh) signal transduction pathway. To assess the role of Gli in embryogenesis, we compared its expression with that of Ptc and Hh family members in mouse. We found that Gli and Ptc are expressed in similar domains in diverse regions of the developing mouse embryo and these regions are adjacent to Hh signals. We also show that Gli is expressed ectopically along with Ptc and Shh in Strong's luxoid mutant mice. These results are consistent with conservation of the Hh signal transduction pathway in mice with Gli potentially mediating Hh signaling in multiple regions of the developing embryo.