Mapping of class I and class II odorant receptors to glomerular domains by two distinct types of olfactory sensory neurons in the mouse

Neuron. 2009 Jan 29;61(2):220-33. doi: 10.1016/j.neuron.2008.11.010.


The repertoire of approximately 1200 odorant receptors (ORs) is mapped onto the array of approximately 1800 glomeruli in the mouse olfactory bulb (OB). The spatial organization of this array is influenced by the ORs. Here we show that glomerular mapping to broad domains in the dorsal OB is determined by two types of olfactory sensory neurons (OSNs), which reside in the dorsal olfactory epithelium. The OSN types express either class I or class II OR genes. Axons from the two OSN types segregate already within the olfactory nerve and form distinct domains of glomeruli in the OB. These class-specific anatomical domains correlate with known functional odorant response domains. However, axonal segregation and domain formation are not determined by the class of the expressed OR protein. Thus, the two OSN types are determinants of axonal wiring, operate at a higher level than ORs, and contribute to the functional organization of the glomerular array.

Publication types

  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Animals
  • Axons / metabolism*
  • Axons / ultrastructure
  • Biomarkers / analysis
  • Body Patterning / genetics
  • Brain Mapping
  • Codon / genetics
  • Gene Expression Regulation, Developmental / genetics
  • Growth Cones / metabolism
  • Growth Cones / ultrastructure
  • Mice
  • Mice, Transgenic
  • Neuropil / metabolism*
  • Neuropil / ultrastructure
  • Olfactory Bulb / metabolism*
  • Olfactory Bulb / ultrastructure
  • Olfactory Nerve / cytology
  • Olfactory Nerve / metabolism*
  • Olfactory Pathways / physiology
  • Olfactory Receptor Neurons / cytology
  • Olfactory Receptor Neurons / metabolism*
  • Receptors, Odorant / classification
  • Receptors, Odorant / genetics*
  • Smell / physiology
  • Synaptic Transmission / physiology


  • Biomarkers
  • Codon
  • Receptors, Odorant