“…PTCH1 is reported to have at least four first exons, 1, 1A, 1B and 1C (Johnson et al, 1996;Hahn et al, 1996a, b;Kogerman et al, 2002;Shimokawa et al, 2004;Nagao et al, 2005), and moreover undergoes exon skipping (Smyth et al, 1998;Nagao et al, 2005) or alternative exon insertion events (Uchikawa et al, 2006). The alternative promoters for exons 1B and 1C have GLI1 binding sites, consequently HH signaling activation results in upregulation of both PTCH1-1B and -1C (Shimokawa et al, 2004).…”