Evidence for gradients of gene expression correlating with zonal topography of the olfactory sensory map.
Signals regulating diversification of olfactory sensory neurons to express odorant receptors and other genes necessary for correct assembly of the olfactory sensory map persist in the olfactory epithelium of adult mouse. We have screened for genes with an expression pattern correlating with the topography odorant receptor-expression zones. The Msx1 homeobox gene and a semaphorin receptor (Neuropilin-2) showed graded expression patterns in the olfactory epithelium. The gradients of Msx1 and Neuropilin-2 expression in basal cells and neurons, respectively, correlated with expression of a retinoic acid-synthesizing enzyme (RALDH2) in lamina propria. A BMP-type I receptor (Alk6) showed a reverse gradient of expression in the supporting cells of the epithelium. Considering known functions of identified genes in cell specification and axon guidance this suggests that zonal division of the olfactory sensory map is maintained, during continuous neurogenesis, as a consequence of topographic counter gradients of positional information.
Norlin
E M
EM
Department of Molecular Biology, Umeå University, Umeå, S-901 87, Sweden.
Alenius
M
M
Gussing
F
F
Hägglund
M
M
Vedin
V
V
Bohm
S
S
D030201:Activin Receptors, Type I / Q000096:biosynthesis / Q000235:genetics; D000445:Aldehyde Oxidoreductases / Q000096:biosynthesis / Q000235:genetics; D000818:Animals; D052005:Bone Morphogenetic Protein Receptors, Type I; D015870:Gene Expression / Q000502:physiology*; D018398:Homeodomain Proteins / Q000096:biosynthesis / Q000235:genetics; D051957:MSX1 Transcription Factor; D051379:Mice; D008810:Mice, Inbred C57BL; D009296:Nasal Cavity / Q000166:cytology / Q000294:innervation* / Q000378:metabolism*; D009419:Nerve Tissue Proteins / Q000096:biosynthesis / Q000235:genetics / Q000378:metabolism; D039942:Neuropilin-1; D009831:Olfactory Mucosa / Q000378:metabolism; D018034:Olfactory Receptor Neurons / Q000378:metabolism*; D017346:Protein Serine-Threonine Kinases; D017978:Receptors, Growth Factor; D050697:Retinal Dehydrogenase; D014157:Transcription Factors
D018398:Homeodomain Proteins; D051957:MSX1 Transcription Factor; D009419:Nerve Tissue Proteins; D017978:Receptors, Growth Factor; D014157:Transcription Factors; D039942:Neuropilin-1; D000445:Aldehyde Oxidoreductases; D050697:Retinal Dehydrogenase; D017346:Protein Serine-Threonine Kinases; D030201:Activin Receptors, Type I; C498215:Bmpr1b protein, mouse; D052005:Bone Morphogenetic Protein Receptors, Type I