spectrum of developmental processes. In some developmental contexts, a gradient of Hh
protein specifies multiple cell types in a dose-dependent fashion, thereby acting as a
morphogen. Hh signaling ultimately acts on the transcriptional level through GLI proteins. In
the presence of Hh signaling full length GLI proteins act as transcriptional activators of target
genes. Conversely, in the absence of Hh, GLI proteins act as transcriptional repressors. This …