Has a dual function as a transcriptional activator and a repressor of the sonic hedgehog (Shh) pathway, and may play a role in limb development. May bind to the minimal GLI-consensus sequence 5'-GGGTGGTC-3' (By similarity). Has an essential role in the early embryonic patterning of mesoderm and neuroectoderm. Phosphorylation is essential for its proteolytic processing. The repressor form (GLI3R), a C-terminally truncated form is generated from the full-length GLI3 protein (GLI3FL) through proteolytic processing. Belongs to the GLI C2H2-type zinc-finger protein family.