The lac repressor, which is produced from the lacl gene, regulates the transcription of the lac operon. The repressor binds to the lac operator to inhibit its transcription.

The operon is regulated by Lac repressor, the product of the lacI gene, which is transcribed from its own promoter (PI). The repressor inhibits transcription by binding to the lac operator (O).

Last week I finally addressed promoters and gave a bit of background on the lac operon. Looking back, I feel that I didn't give the topic of operons adequate treatment. They are a very crucial ...