Figure 1 Comparison of a simple eukaryotic promoter and extensively diversified metazoan regulatory modules. a, Simple eukaryotic transcriptional unit. A simple core promoter (TATA), upstream activator sequence (UAS) and silencer element spaced within 100200 bp of the TATA box that is typically found in unicellular eukaryotes. b, Complex metazoan transcriptional control modules. A complex arrangement of multiple clustered enhancer modules interspersed with silencer and insulator elements which can be located 1050 kb either upstream or downstream of a composite core promoter containing TATA box (TATA), Initiator sequences (INR), and downstream promoter elements (DPE).