Wiktionary
n. A group of genes that is regulated by the same regulatory molecule. The genes of a regulon share a common regulatory element binding site or promoter. The genes comprising a regulon may be located non-contiguously in the genome.
Wikipedia
In molecular genetics, a regulon is a group of genes that are regulated as a unit, generally controlled by the same regulatory gene that expresses a protein acting as a repressor or activator. This terminology is generally, although not exclusively, used in reference to prokaryotes, whose genomes are often organized into operons; the genes contained within a regulon are usually organized into more than one operon at disparate locations on the chromosome. Applied to eukaryotes, the term refers to any group of non-contiguous genes controlled by the same regulatory gene.
A modulon is a set of regulons or operons that are collectively regulated in response to changes in overall conditions or stresses, but may be under the control of different or overlapping regulatory molecules. The term stimulon is sometimes used to refer to the set of genes whose expression responds to specific environmental stimuli.
Usage examples of "regulon".
It is hard to see how you save the carousel and the musical horse in a world of video games, not because the carousel and musical horse are less attractive to children than the Game Boy, but because the carousel and the musical horse are single things in one fixed place and the video games are everywhere, no Regulon to eat them up.