Marx, Christopher J. 2011. “Regulatory Revolution: Evolving the ‘Anti-LacI’ Repressor.” Cell 146 (3) (August): 350–352. doi:10.1016/j.cell.2011.07.015.
Much of adaptation is based upon changes in gene expression, but the emergence of new regulatory logic has not been observed directly. Now, Poelwijk et al. report evolving the lac repressor (LacI) to reverse its regulatory logic, resulting in an “anti-LacI” that represses transcription when bound to its “inducer.”