Phosphatidyl-inositide signalling proteins in a novel class of sensory cells in the mammalian olfactory epithelium.
Ciliated sensory neurons, supporting cells and basal stem cells represent major cellular components of the main olfactory epithelium in mammals. Here we describe a novel class of sensory cells in the olfactory neuroepithelium. The cells express phospholipase C beta-2 (PLC beta2), transient receptor potential channels 6 (TRPC6) and inositol 3, 4, 5-trisphosphate receptors type III (InsP3R-III). Unlike ciliated olfactory neurons, they express neither olfactory marker protein nor centrin, adenylyl cyclase or cyclic nucleotide-gated cation channels. Typical components of the cytoskeleton of microvilli, ezrin and actin are found co-localized with PLC beta2 and TRPC6 in apical protrusions of the cells. In Ca2+-imaging experiments, the cells responded to odours. They express neuronal marker proteins and possess an axon-like process, but following bulbectomy the cells do not degenerate. Our results suggest a novel class of microvillous secondary chemosensory cells in the mammalian olfactory system. These cells, which utilize phosphatidyl-inositides in signal transduction, represent about 5% of all olfactory cells. Their abundance indicates that they play an important role in stimulus-dependent functions and/or the regeneration of the olfactory system.
Elsaesser
Rebecca
R
Institute of General Zoology and Animal Physiology, Friedrich-Schiller-University, D-07743 Jena, Germany. selsaes3@jhem.jhmi.edu
Montani
Giorgia
G
Tirindelli
Roberto
R
Paysan
Jacques
J
D000818:Animals; D001483:Base Sequence; D015220:Calcium Channels / Q000235:genetics* / Q000502:physiology; D017931:DNA Primers; D004847:Epithelial Cells / Q000502:physiology; D017930:Genes, Reporter; D049452:Green Fluorescent Proteins / Q000032:analysis / Q000235:genetics; D007150:Immunohistochemistry; D053496:Inositol 1,4,5-Trisphosphate Receptors; D007527:Isoenzymes / Q000235:genetics*; D051379:Mice; D008822:Mice, Transgenic; D008871:Microvilli / Q000201:enzymology / Q000502:physiology; D009475:Neurons, Afferent / Q000502:physiology; D009830:Olfactory Bulb / Q000502:physiology*; D009831:Olfactory Mucosa / Q000166:cytology / Q000187:drug effects / Q000201:enzymology / Q000502:physiology*; D010716:Phosphatidylinositols / Q000494:pharmacology*; D054799:Phospholipase C beta; D016133:Polymerase Chain Reaction; D018160:Receptors, Cytoplasmic and Nuclear / Q000235:genetics / Q000502:physiology; D015398:Signal Transduction / Q000187:drug effects / Q000502:physiology; D050052:TRPC Cation Channels; D000074287:TRPC6 Cation Channel; D010738:Type C Phospholipases / Q000235:genetics*
D015220:Calcium Channels; D017931:DNA Primers; D053496:Inositol 1,4,5-Trisphosphate Receptors; D007527:Isoenzymes; D010716:Phosphatidylinositols; D018160:Receptors, Cytoplasmic and Nuclear; D050052:TRPC Cation Channels; D000074287:TRPC6 Cation Channel; C492146:Trpc6 protein, mouse; D049452:Green Fluorescent Proteins; D010738:Type C Phospholipases; D054799:Phospholipase C beta; C518037:Plcb2 protein, mouse