Mouse SHH is part of a small group of secreted proteins that are vital for development in both vertebrates and invertebrates. Mouse SHH shares 99% homology with the human gene for SHH. Sonic HedgeHog is a protein that is vital in guiding the early embryo; it has been associated as the major inductive signal in patterning of the ventral neural tube, the anterior-posterior limb axis, and the ventral somites. SHH binds to the patched receptor to activate the transcription of target genes. Sonic HedgeHog also regulates another factor, the gli oncogene. Recombinant Mouse SHH is a single, non-glycosylated polypeptide chain of 19.8 kDa.