Controlling gene expression with lactose

Photo by Mehrshad Rajabi on Unsplash

The first gene regulatory mechanism to be described and understood was the lac operon, involved in the transport and metabolism of lactose. An operon is a DNA unit controlled by a single promoter that regulates the expression of a cluster of genes. In the case of lac, it contains the information needed for the transport as well as the metabolic enzymes needed to break down lactose.