Enhancer: a given site binds regulator responsible for activating the gene Alternative enhancer binds different groups of regulators and control expression of the same gene at different times and laces in responsible to different signals. Activation at a distance is much more common in eukaryotes. Insulators(绝缘体 or boundary elements are regulatory sequences to ensure a linked promoter not responding to the activator bindingEnhancer: a given site binds regulator responsible for activating the gene. Alternative enhancer binds different groups of regulators and control expression of the same gene at different times and places in responsible to different signals. Activation at a distance is much more common in eukaryotes. Insulators (绝缘体) or boundary elements are regulatory sequences to ensure a linked promoter not responding to the activator binding