Gene switch for odorant receptors
The olfactory sensory neurons in the nasal mucosa perceive the myriad smells in the air with the aid of odorant receptors. Each sensory neuron chooses one and only one receptor gene for expression. The probability that a particular receptor gene is chosen for expression determines how many olfactory sensory neurons in total produce this receptor type. Scientists from the Max Planck Institute of Biophysics in Frankfurt have unveiled an aspect of how the probability of the choice of an odorant receptor gene is regulated in olfactory sensory neurons. Regulatory elements in the genome regulate the probability of the choice of individual odorant receptor genes within a gene cluster. These elements act as on-off-switches for gene choice, but they do not regulate the number of receptor molecules that are produced by a cell once a particular gene is chosen for expression.