Regulon

As regulon is referred to in the genetics a group of independent genes (or operon ), whose transcription by a common regulator ( repressor or activator is controlled).

Examples

Catabolite repression : The activator CAP (Catabolite Activator Protein), activated in the presence of cAMP u. a. the transcription of the lactose operon ( lac operon).
Another example is the tryptophan repressor (TrpR) in the genome of the bacterium Escherichia coli . The protein not only represses its own transcription on the trpR gene and that of tryptophan on the trp operon , but also the transcription of the aroH operon. The latter codes for proteins that the cell needs for the synthesis of all aromatic amino acids.
Regulons are also used as a response to heat shock in bacteria. The sigma factor σ32 (encoded by the RpoH gene) regulates 89 different open reading frames (ORFs), which are indicative of coding areas.

Nancy Trun & Janine Trempy (2003): Gene Expression and Regulation. In: Fundamental Bacterial Genetics. ISBN 0632044489 PDF