The Dlx5 homeodomain gene is essential for olfactory development and connectivity in the mouse.
The distalless-related homeogene Dlx5 is expressed in the olfactory placodes and derived tissues and in the anterior-basal forebrain. We investigated the role of Dlx5 in olfactory development. In Dlx5(-/-) mice, the olfactory bulbs (OBs) lack glomeruli, exhibit disorganized cellular layers, and show reduced numbers of TH- and GAD67-positive neurons. The olfactory epithelium in Dlx5(-/-) mice is composed of olfactory receptor neurons (ORNs) that appear identical to wild-type ORNs, but their axons fail to contact the OBs. We transplanted Dlx5(-/-) OBs into a wild-type newborn mouse; wild-type ORN axons enter the mutant OB and form glomeruli, but cannot rescue the lamination defect or the expression of TH and GAD67. Thus, the absence of Dlx5 in the OB does not per se prevent ORN axon ingrowth. In conclusion, Dlx5 plays major roles in the connectivity of ORN axons and in the differentiation of OB interneurons.
Laboratoire de Physiologie Général et Comparée, CNRS, UMR 8572, Museum National d'Histoire Naturelle, Paris, France.
Giovanni
G
Levi
Adam C
AC
Puche
Stefano
S
Mantero
Ottavia
O
Barbieri
Sonya
S
Trombino
Laura
L
Paleari
Aliana
A
Egeo
Giorgio R
GR
Merlo
D000818:Animals; D000831:Animals, Newborn; D016380:Brain Tissue Transplantation; D002395:Catecholamines / Q000096:biosynthesis / Q000235:genetics; D002454:Cell Differentiation / Q000235:genetics; D005333:Fetus; D018507:Gene Expression Regulation, Developmental / Q000235:genetics; D020439:Growth Cones / Q000378:metabolism*; D018398:Homeodomain Proteins / Q000235:genetics / Q000378:metabolism*; D007395:Interneurons / Q000166:cytology / Q000378:metabolism; D051379:Mice; D018345:Mice, Knockout; D009830:Olfactory Bulb / Q000196:embryology* / Q000254:growth & development / Q000637:transplantation; D009831:Olfactory Mucosa / Q000196:embryology* / Q000254:growth & development / Q000378:metabolism; D009832:Olfactory Nerve / Q000196:embryology* / Q000254:growth & development / Q000378:metabolism; D013569:Synapses / Q000235:genetics / Q000378:metabolism; D005680:gamma-Aminobutyric Acid / Q000096:biosynthesis / Q000235:genetics
D002395:Catecholamines; C501120:Dlx5 protein, mouse; D018398:Homeodomain Proteins; D005680:gamma-Aminobutyric Acid