Hoxa2- and rhombomere-dependent development of the mouse facial somatosensory map.
In the mouse trigeminal pathway, sensory inputs from distinct facial structures, such as whiskers or lower jaw and lip, are topographically mapped onto the somatosensory cortex through relay stations in the thalamus and hindbrain. In the developing hindbrain, the mechanisms generating such maps remain elusive. We found that in the principal sensory nucleus, the whisker-related map is contributed by rhombomere 3-derived neurons, whereas the rhombomere 2-derived progeny supply the lower jaw and lip representation. Moreover, early Hoxa2 expression in neuroepithelium prevents the trigeminal nerve from ectopically projecting to the cerebellum, whereas late expression in the principal sensory nucleus promotes selective arborization of whisker-related afferents and topographic connectivity to the thalamus. Hoxa2 inactivation further results in the absence of whisker-related maps in the postnatal brain. Thus, Hoxa2- and rhombomere 3-dependent cues determine the whisker area map and are required for the assembly of the whisker-to-barrel somatosensory circuit.
Oury
Franck
F
Institut de Génétique et de Biologie Moléculaire et Cellulaire, CNRS/INSERM/Université Louis Pasteur, UMR 7104, BP 10142, Communauté Urbaine de Strasbourg, 67404 Illkirch Cedex, France.
Murakami
Yasunori
Y
Renaud
Jean-Sebastien
JS
Pasqualetti
Massimo
M
Charnay
Patrick
P
Ren
Shu-Yue
SY
Rijli
Filippo M
FM
D000344:Afferent Pathways; D000818:Animals; D001369:Axons / Q000648:ultrastructure; D005145:Face / Q000294:innervation; D018398:Homeodomain Proteins / Q000235:genetics / Q000502:physiology*; D008046:Lip / Q000294:innervation; D008334:Mandible / Q000196:embryology / Q000294:innervation; D051379:Mice; D008822:Mice, Transgenic; D009154:Mutation; D009475:Neurons, Afferent / Q000166:cytology; D036122:Receptor, EphA4 / Q000378:metabolism; D036141:Receptor, EphA7 / Q000378:metabolism; D012249:Rhombencephalon / Q000166:cytology / Q000196:embryology* / Q000378:metabolism; D013003:Somatosensory Cortex / Q000033:anatomy & histology* / Q000196:embryology; D013788:Thalamus / Q000196:embryology / Q000378:metabolism; D012668:Trigeminal Ganglion / Q000196:embryology / Q000378:metabolism; D014276:Trigeminal Nerve / Q000196:embryology* / Q000502:physiology; D020651:Ventral Thalamic Nuclei / Q000196:embryology; D014738:Vibrissae / Q000294:innervation*
D018398:Homeodomain Proteins; C489833:Hoxa2 protein, mouse; D036122:Receptor, EphA4; D036141:Receptor, EphA7