3.26 - Mammalian Odorant Receptor Gene Regulation

Mammals cope with the vast diversity of odor molecules by employing hundreds of odorant receptors (ORs). Each mature olfactory sensory neuron expresses only one allele of one OR gene, an adaptation that maximizes odor discrimination ability. This specificity is achieved via a developmental program of epigenetic repression and segregation of OR gene loci into compartments within the nucleus, rescue of a few OR genes from repression in each immature neuron, and an unprecedented mechanism involving interchromosomal interactions between OR gene enhancers to trigger strong expression of a single OR allele and the final maturation of the sensory neuron.