Operons An operon is a cluster of coordinately regulated genes. It contains Structural genes: encode enzymes Regulatory genes: encode repressors or activators of expression Regulatory sites: e.g. promoters, operatorsOperons • An operon is a cluster of coordinately regulated genes. It contains: • Structural genes: encode enzymes • Regulatory genes: encode repressors or activators of expression • Regulatory sites: e.g. promoters, operators