Variation in olfactory neuron repertoires is genetically controlled and environmentally modulated

Area of Science:

• Neuroscience
• Genetics
• Olfactory Research

Background:

• The mouse nose contains millions of olfactory sensory neurons (OSNs), each expressing one of over 1000 olfactory receptor (OR) genes, creating numerous OSN subtypes.
• Understanding the factors that generate this neuronal diversity is crucial for comprehending olfactory processing.

Purpose of the Study:

• To develop and validate an RNA-sequencing method for quantifying OSN subtype abundance.
• To investigate the genetic and environmental influences on OSN diversity.

Main Methods:

• RNA sequencing was employed to quantify the abundance of all OSN subtypes simultaneously.
• Comparative analysis was performed across different mouse strains and conditions.

Main Results:

• OSN subtype distribution is consistent in genetically identical mice but varies significantly between strains.
• Cis-acting genetic variation was identified as the primary driver of OSN composition, independent of OR function.
• Exposure to specific odorants reproducibly modulated dozens of OSN subtypes in a time-dependent manner.

Conclusions:

• Genetic factors, particularly cis-acting variations, play a dominant role in establishing OSN diversity.
• Environmental factors, such as odor stimulation, can fine-tune OSN populations.
• These combined mechanisms contribute to a highly individualized olfactory system.