Tissue-specific enhancer action

(a) The limb-specific enhancer binds different, limb-specific transcription factors to express SHH differently in limb cells. (b) A different brain-specific enhancer is bound by brain-specific transcription factors and activates SHH transcription in brain cells(a) The limb-specific enhancer binds different, limb-specific transcription factors to express SHH differently in limb cells. (b) A different brain-specific enhancer is bound by brain-specific transcription factors and activates SHH transcription in brain cells

(a) Limb cells Limb-specific transcription factors (b) Brain cells Brain-specific transcription factors enhancer enhancer