GLI3(Gli-kruppel family member 3), also called ONCOGENE GLI3, encodes a member of the zinc finger gene family related to Kruppel, a gene that is known to regulate development in Drosophila. The GLI3 gene is expressed as an 8.5-kb mRNA in tissues such as testis, myometrium, placenta, and lung, and the protein product (relative molecular mass, 190,000) shows sequence-specific DNA binding. The GLI3 gene is mapped on 7p14.1. GLI3 is homologous to the Drosophila cubitus interruptus (ci) gene product (Ci), which regulates the Patched (pct), gooseberry (gsb), and decapentaplegic (dpp) genes. PKA-dependent processing of vertebrate GLI3 in developing limb generates a potent repressor in a manner antagonized by apparent long-range signaling from posteriorly localized Sonic hedgehog protein. The high relative abundance and potency of GLI3 repressor suggested specialization of GLI3 and its products for negative hedgehog pathway regulation.Coimmunoprecipitation and immunoblot studies showed that GLI3 protein is polyubiquitinated and that its processing depends on proteasome activity. The findings suggested that BTRC is required for GLI3 processing.