A unique cell population in the mouse olfactory bulb displays nuclear beta-catenin signaling during development and olfactory sensory neuron regeneration.
Olfactory sensory neurons (OSNs) in the nose form precise connections with neurons in the brain. However, mechanisms that account for the formation of such precise neuronal connections are incompletely understood. Recent studies implicate the function of Wnt growth factors in the formation of neuronal connections. To assess the role of Wnt signaling in the olfactory system, we examined the expression of beta-galactosidase (beta-gal) in the TOPGAL mouse, a transgenic strain in which beta-gal expression reports the activation of the canonical Wnt signaling pathway. In the olfactory epithelium, no beta-gal expression was observed at any developmental stages. In the olfactory bulb (OB), beta-gal expression was observed in a population of cells located at the interface of the olfactory nerve layer and the glomerular layer. The beta-gal expression was developmentally regulated with the peak expression occurring at late embryonic and early postnatal stages and a greatly reduced expression in adulthood. Further, forced OSN regeneration and subsequent reinnervation of the OB led to a reactivation of beta-gal expression in mature animals. The temporal coincidence between the peak of beta-gal expression and formation of OSN connections, together with the spatial localization of these cells, suggests a potential role of these cells and canonical Wnt signaling in the formation of OSN connections in the OB during development and regeneration.
Booker-Dwyer
Tiara
T
Department of Biology, Johns Hopkins University, Baltimore, Maryland 21218, USA.
Hirsh
Sarah
S
Zhao
Haiqing
H
D000818:Animals; D000831:Animals, Newborn; D013956:Antithyroid Agents / Q000008:administration & dosage; D001973:Bromodeoxyuridine / Q000378:metabolism; D002478:Cells, Cultured; D004622:Embryo, Mammalian; D005732:Gangliosides / Q000378:metabolism; D018507:Gene Expression Regulation, Developmental / Q000187:drug effects / Q000502:physiology*; D051821:Lymphoid Enhancer-Binding Factor 1 / Q000235:genetics / Q000378:metabolism; D008713:Methimazole / Q000008:administration & dosage; D051379:Mice; D008822:Mice, Transgenic; D009416:Nerve Regeneration / Q000187:drug effects / Q000502:physiology*; D009419:Nerve Tissue Proteins / Q000235:genetics / Q000378:metabolism; D009475:Neurons, Afferent / Q000187:drug effects / Q000502:physiology*; D009830:Olfactory Bulb / Q000166:cytology* / Q000196:embryology / Q000254:growth & development; D015398:Signal Transduction / Q000187:drug effects / Q000235:genetics / Q000502:physiology*; D051820:TCF Transcription Factors / Q000235:genetics / Q000378:metabolism; D051153:Wnt Proteins / Q000235:genetics / Q000378:metabolism; D051176:beta Catenin / Q000235:genetics / Q000378:metabolism*; D001616:beta-Galactosidase / Q000235:genetics
D013956:Antithyroid Agents; D005732:Gangliosides; C497574:Lef1 protein, mouse; D051821:Lymphoid Enhancer-Binding Factor 1; D009419:Nerve Tissue Proteins; D051820:TCF Transcription Factors; D051153:Wnt Proteins; D051176:beta Catenin; C062875:ganglioside A2B5; D008713:Methimazole; D001616:beta-Galactosidase; D001973:Bromodeoxyuridine