Binding site is the place on cellular DNA to which a protein (like transcription factor) can bind. Typically, binding sites may be found in the vicinity of genes, and would be involved in activating the transcription of that gene (promoter elements), in enhancing the transcription of that gene (enhancer elements), or in reducing transcription of that gene (silencers). NOTE that whether the protein in fact performs these functions might rely on some condition, such as the presence of the hormone, or the tissue in which the gene is being examined. Binding sites could also be involved in the regulation of chromosome structure or of DNA replication.