Olfactory epithelium influences the orientation of mitral cell dendrites during development.
We have established previously that, although the olfactory epithelium is absent in the homozygous Pax-6 mutant mouse, an olfactory bulb-like structure (OBLS) does develop. Moreover, this OBLS contains cells that correspond to mitral cells, the primary projection neurons in the olfactory bulb. The current study aimed to address whether the dendrites of mitral cells in the olfactory bulb or in the OBLS mitral-like cells, exhibit a change in orientation in the presence of the olfactory epithelium. The underlying hypothesis is that the olfactory epithelium imparts a trophic signal on mitral and mitral-like cell that influences the growth of their primary dendrites, orientating them toward the surface of the olfactory bulb. Hence, we cultured hemibrains from wild-type and Pax 6 mutant mice from two different embryonic stages (embryonic days 14 and 15) either alone or in coculture with normal olfactory epithelial explants or control tissue (cerebellum). Our results indicate that the final dendritic orientation of mitral and mitral-like cells is directly influenced both by age and indeed by the presence of the olfactory epithelium.
López-Mascaraque
Laura
L
Instituto Cajal (CSIC), Ave. Doctor Arce 37, 28002 Madrid, Spain. mascaraque@cajal.csic.es
García
Concepción
C
Blanchart
Albert
A
De Carlos
Juan A
JA
D000818:Animals; D001921:Brain / Q000378:metabolism; D002232:Carbocyanines / Q000737:chemistry; D002478:Cells, Cultured; D018920:Coculture Techniques; D003094:Collagen / Q000737:chemistry; D004396:Coloring Agents / Q000494:pharmacology; D003712:Dendrites / Q000378:metabolism*; D004848:Epithelium / Q000196:embryology* / Q000378:metabolism*; D005136:Eye Proteins / Q000235:genetics / Q000378:metabolism / Q000502:physiology; D018507:Gene Expression Regulation, Developmental; D006579:Heterozygote; D018398:Homeodomain Proteins / Q000235:genetics / Q000378:metabolism / Q000502:physiology; D006720:Homozygote; D051379:Mice; D008856:Microscopy, Fluorescence; D009154:Mutation; D009474:Neurons / Q000378:metabolism; D009831:Olfactory Mucosa / Q000196:embryology* / Q000378:metabolism*; D018034:Olfactory Receptor Neurons / Q000196:embryology*; D000071841:PAX6 Transcription Factor; D051761:Paired Box Transcription Factors; D012097:Repressor Proteins / Q000235:genetics / Q000378:metabolism / Q000502:physiology; D013687:Telencephalon / Q000378:metabolism; D013997:Time Factors
D002232:Carbocyanines; D004396:Coloring Agents; D005136:Eye Proteins; D018398:Homeodomain Proteins; D000071841:PAX6 Transcription Factor; D051761:Paired Box Transcription Factors; C000605732:Pax6 protein, mouse; D012097:Repressor Proteins; D003094:Collagen