| Although the operon model has proved a useful model of gene regulation in bacteria, different regulatory mechanisms are employed in eukaryotes. |
| Recently, the development of inducible expression systems has involved exploitation of the p-cym operon from Pseudomonas putida. |
| If lactose enters the cell, it binds to the lac repressor and induces a change of shape in the repressor so that it can no longer bind to the DNA at the operon. |
| Mutations in the gene mexR coding for the repressor protein result in reduced affinity for the promoter target and upregulation of the mexAB-oprM operon. |
| A lower intensity of mutagenesis can explain all observed revertants if each mutagenized cell has multiple copies of the lac operon. |
| In addition to the lac operon, a number of other synthetic and natural genetic circuits have been analyzed for robustness and evolvability. |
