Chemical Senses Advance Access originally published online on May 20, 2008
Chemical Senses 2008 33(6):531-539; doi:10.1093/chemse/bjn021
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BDNF Promoter–Mediated β-Galactosidase Expression in the Olfactory Epithelium and Bulb
1 Department of Cell and Developmental Biology, Neuroscience Program and Rocky Mountain Taste and Smell Center, University of Colorado Denver School of Medicine, MS 8108 Box 6511, Aurora, CO 80045, USA 2 Department of Molecular, Cellular, and Developmental Biology, University of Colorado, Boulder, CO 80309, USA
Correspondence to be sent to: Diego Restrepo, Department of Cell and Developmental Biology, University of Colorado Denver, Mail Stop 8108, PO BOX 6511, Aurora CO 80045, USA. e-mail: diego.restrepo{at}uchsc.edu
| Abstract |
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The neurotrophin brain-derived neurotrophic factor (BDNF) has been implicated in the generation and differentiation of new olfactory sensory neurons (OSNs) and in the regulation of branching of OSN axons in their target glomeruli. However, previous reports of BDNF mRNA and protein expression in olfactory epithelium and olfactory bulb (OB) have been inconsistent, raising questions on the proposed roles for BDNF. Here, we report on β-galactosidase (β-gal) expression in adult gene-targeted mice where the BDNF promoter drives expression of the Escherichia coli lacZ gene (BDNFlacZneo mice). We find that β-gal is expressed in a small subset of OSNs with axons that reach the olfactory nerve layers throughout the OB. In the OB, we find expression of β-gal in
-aminobutyric acidergic but not dopaminergic periglomerular cells and external tufted cells and in interneurons located in the mitral cell layer. Our results are inconsistent with the regulation of generation and differentiation of new OSNs elicited by the release of BDNF from horizontal basal cells. The results are consistent with a role for BDNF in competitive branching of OSN axons within the glomeruli of the OB.
Key words: BDNF, neurotrophin, olfactory bulb, olfactory sensory neurons, periglomerular cells
Accepted 9 April 2008