Regulator gene

A regulator gene or regulatory gene is a gene involved in controlling the expression of one or more other genes. A regulator gene may encode a protein, or it may work at the level of RNA, as in the case of genes encoding microRNAs.

In prokaryotes, regulator genes often codes for repressor proteins. Repressor proteins bind to operators or promoters, preventing RNA polymerase from transcribing RNA. Inducers cause repressor proteins to change shape or otherwise become unable to bind DNA, allowing RNA polymerase to continue transcription.