Mutually Exclusive Glomerular Innervation by Two Distinct Types of Olfactory Sensory Neurons Revealed in Transgenic Zebrafish

The olfactory epithelium of fish contains two major types of olfactory sensory neurons (OSNs) that are distinct morphologically (ciliated vs microvillous) and possibly functionally. Here, we found that these OSNs express different sets of signal transduction machineries: the ciliated OSNs express OR-type odorant receptors, cyclic nucleotide-gated channel A2 subunit, and olfactory marker protein (OMP), whereas the microvillous OSNs express V2R-type receptors and transient receptor potential channel C2 (TRPC2). To visualize patterns of axonal projection from the two types of OSNs to the olfactory bulb (OB), we generated transgenic zebrafish in which spectrally distinct fluorescent proteins are expressed in the ciliated and microvillous OSNs under the control of OMP and TRPC2 gene promoters, respectively. An observation of whole-mount OB in adult double-transgenic zebrafish revealed that the ciliated OSNs project axons mostly to the dorsal and medial regions of the OB, whereas the microvillous OSNs project axons to the lateral region of the OB. A careful histological examination of OB sections clarified that the axons from the two distinct types of OSNs target different glomeruli in a mutually exclusive manner. This segregation is already established at very early developmental stages in zebrafish embryos. These findings clearly demonstrate the relationships among cell morphology, molecular signatures, and axonal terminations of the two distinct types of OSNs and suggest that the two segregated neural pathways are responsible for coding and processing of different types of odor information in the zebrafish olfactory system.

[1]  H. Okamoto,et al.  Robo2 is required for establishment of a precise glomerular map in the zebrafish olfactory system , 2005, Development.

[2]  T. Finger,et al.  Phyletic Distribution of Crypt-Type Olfactory Receptor Neurons in Fishes , 2000, Brain, Behavior and Evolution.

[3]  L. Stryer,et al.  Cloning and localization of two multigene receptor families in goldfish olfactory epithelium. , 1998, Proceedings of the National Academy of Sciences of the United States of America.

[4]  A. Martínez-Marcos,et al.  Structure and function of the vomeronasal system: an update , 2003, Progress in Neurobiology.

[5]  Makiko Suwa,et al.  Structural Basis for a Broad But Selective Ligand Spectrum of a Mouse Olfactory Receptor: Mapping the Odorant-Binding Site , 2005, The Journal of Neuroscience.

[6]  David H. Evans,et al.  The Physiology of Fishes , 1994 .

[7]  H. Okano,et al.  A Genetic Approach to Visualization of Multisynaptic Neural Pathways Using Plant Lectin Transgene , 1999, Neuron.

[8]  M. S. Singer,et al.  Analysis of the molecular basis for octanal interactions in the expressed rat 17 olfactory receptor. , 2000, Chemical senses.

[9]  K. Yau,et al.  Primary structure and functional expression of a cyclic nucleotide-activated channel from olfactory neurons , 1990, Nature.

[10]  S. Korsching,et al.  Selective targeting of zebrafish olfactory receptor neurons by the endogenous OMP promoter , 2002, The European journal of neuroscience.

[11]  H. Baier,et al.  Olfactory glomeruli in the zebrafish form an invariant pattern and are identifiable across animals , 1994, The Journal of neuroscience : the official journal of the Society for Neuroscience.

[12]  Alison L. Barth,et al.  Noncoordinate Expression of Odorant Receptor Genes Tightly Linked in the Zebrafish Genome , 1997, Neuron.

[13]  A. Chess,et al.  The family of genes encoding odorant receptors in the channel catfish , 1993, Cell.

[14]  G M Shepherd,et al.  Molecular mechanisms underlying differential odor responses of a mouse olfactory receptor. , 2000, Proceedings of the National Academy of Sciences of the United States of America.

[15]  T. Finger,et al.  Differential projections of ciliated and microvillous olfactory receptor cells in the catfish, Ictalurus punctatus , 1998, The Journal of comparative neurology.

[16]  K. Sato,et al.  Whole-cell response characteristics of ciliated and microvillous olfactory receptor neurons to amino acids, pheromone candidates and urine in rainbow trout. , 2001, Chemical senses.

[17]  T. Finger,et al.  Differential distribution of olfactory receptor neurons in goldfish: Structural and molecular correlates , 2004, The Journal of comparative neurology.

[18]  L. Prézeau,et al.  Evolution, structure, and activation mechanism of family 3/C G-protein-coupled receptors. , 2003, Pharmacology & therapeutics.

[19]  E. Yildirim,et al.  The mouse C-type transient receptor potential 2 (TRPC2) channel: Alternative splicing and calmodulin binding to its N terminus , 2003, Proceedings of the National Academy of Sciences of the United States of America.

[20]  Donghui Kuang,et al.  Molecular Similarities in the Ligand Binding Pockets of an Odorant Receptor and the Metabotropic Glutamate Receptors* , 2003, Journal of Biological Chemistry.

[21]  Peter Mombaerts,et al.  Genes and ligands for odorant, vomeronasal and taste receptors , 2004, Nature Reviews Neuroscience.

[22]  R. Friedrich,et al.  Combinatorial and Chemotopic Odorant Coding in the Zebrafish Olfactory Bulb Visualized by Optical Imaging , 1997, Neuron.

[23]  F. Weltzien,et al.  Does the lateral bundle of the medial olfactory tract mediate reproductive behavior in male crucian carp? , 2003, Chemical senses.

[24]  P. Sorensen,et al.  Sex pheromones selectively stimulate the medial olfactory tracts of male goldfish , 1991, Brain Research.

[25]  Takao Nakamura,et al.  Identification of membrane-type receptor for bile acids (M-BAR). , 2002, Biochemical and biophysical research communications.

[26]  E H Hamdani,et al.  Is feeding behaviour in crucian carp mediated by the lateral olfactory tract? , 2001, Chemical senses.

[27]  T. Finger,et al.  Correlation between Olfactory Receptor Cell Type and Function in the Channel Catfish , 2003, The Journal of Neuroscience.

[28]  H. Baier,et al.  Connectional topography in the zebrafish olfactory system: random positions but regular spacing of sensory neurons projecting to an individual glomerulus. , 1994, Proceedings of the National Academy of Sciences of the United States of America.

[29]  E. Isacoff,et al.  Functional Identification of a Goldfish Odorant Receptor , 1999, Neuron.

[30]  K. Døving,et al.  Alarm reaction in the crucian carp is mediated by the medial bundle of the medial olfactory tract. , 2000, Chemical senses.

[31]  R. Axel,et al.  The molecular logic of smell. , 1995, Scientific American.

[32]  Alison L. Barth,et al.  Asynchronous Onset of Odorant Receptor Expression in the Developing Zebrafish Olfactory System , 1996, Neuron.

[33]  E. Brown,et al.  The extracellular calcium receptor. , 1995, Current opinion in cell biology.

[34]  S. Itohara,et al.  Laminar organization of the developing lateral olfactory tract revealed by differential expression of cell recognition molecules , 2004, The Journal of comparative neurology.

[35]  L. Buck,et al.  The Molecular Architecture of Odor and Pheromone Sensing in Mammals , 2000, Cell.

[36]  T. Gudermann,et al.  Cloning, expression and subcellular localization of two novel splice variants of mouse transient receptor potential channel 2. , 2000, The Biochemical journal.

[37]  Takeharu Nagai,et al.  Shift anticipated in DNA microarray market , 2002, Nature Biotechnology.

[38]  R. Tsien,et al.  A monomeric red fluorescent protein , 2002, Proceedings of the National Academy of Sciences of the United States of America.

[39]  D. Lipschitz,et al.  Amino acid odorants stimulate microvillar sensory neurons. , 2002, Chemical senses.

[40]  M. Peyton,et al.  Mouse trp2, the homologue of the human trpc2 pseudogene, encodes mTrp2, a store depletion-activated capacitative Ca2+ entry channel. , 1999, Proceedings of the National Academy of Sciences of the United States of America.

[41]  Rainer W. Friedrich,et al.  Chemotopic, Combinatorial, and Noncombinatorial Odorant Representations in the Olfactory Bulb Revealed Using a Voltage-Sensitive Axon Tracer , 1998, The Journal of Neuroscience.

[42]  M. Mishina,et al.  Regulation by Protein Kinase A Switching of Axonal Pathfinding of Zebrafish Olfactory Sensory Neurons through the Olfactory Placode–Olfactory Bulb Boundary , 2002, The Journal of Neuroscience.

[43]  S. Nakanishi,et al.  A family of metabotropic glutamate receptors , 1992, Neuron.

[44]  K. Døving,et al.  Projection of sensory neurons with microvilli to the lateral olfactory tract indicates their participation in feeding behaviour in crucian carp. , 2001, Chemical senses.

[45]  Richard Axel,et al.  Coding of olfactory information: Topography of odorant receptor expression in the catfish olfactory epithelium , 1993, Cell.

[46]  L. S. Demski,et al.  Functional-anatomical studies on sperm release evoked by electrical stimulation of the olfactory tract in goldfish , 1984, Brain Research.

[47]  G. Montalbano,et al.  S100 protein-like immunoreactivity in the crypt olfactory neurons of the adult zebrafish , 2004, Neuroscience Letters.

[48]  Jinhong Fan,et al.  Molecular Determinants of Ligand Selectivity in a Vertebrate Odorant Receptor , 2004, The Journal of Neuroscience.

[49]  K. Døving,et al.  The alarm reaction in crucian carp is mediated by olfactory neurons with long dendrites. , 2002, Chemical senses.

[50]  Masataka Harada,et al.  A G Protein-coupled Receptor Responsive to Bile Acids* , 2003, The Journal of Biological Chemistry.

[51]  H. Zippel,et al.  In goldfish the qualitative discriminative ability for odors rapidly returns after bilateral nerve axotomy and lateral olfactory tract transection , 1993, Brain Research.