Trio controls the mature organization of neuronal clusters in the hindbrain.
During the embryonic development of the hindbrain, movements of neuronal clusters allow the formation of mature "pools", in particular for inferior olivary (ION) and facial motor (fMN) nuclei. The cellular mechanisms of neuron clustering remain uncharacterized. We report that the absence of the Rho-guanine exchange factor Trio, which can activate both RhoG and Rac1 in vivo, prevents the proper formation of ION and fMN subnuclei. Rac1, but not RhoG, appears to be a downstream actor in Trio-induced lamellation. In addition, we report that Cadherin-11 is expressed by a subset of neurons through the overall period of ION and fMN parcellations, and defects observed in trio mutant mice are located specifically in Cadherin-11-expressing regions. Moreover, endogenous Cadherin-11 is found in a complex with Trio when lamellation occurs. Altogether, those results establish a link between Trio activity, the subsequent Rac1 activation, and neuronal clusters organization, as well as a possible recruitment of the Cadherin-11 adhesive receptor to form a complex with Trio.
Backer
Stéphanie
S
Institut Cochin, Université Paris Descartes, Centre National de la Recherche Scientifique, Unité Mixte de Recherche 8104, 75014 Paris, France.
Hidalgo-Sánchez
Matías
M
Offner
Nicolas
N
Portales-Casamar
Elodie
E
Debant
Anne
A
Fort
Philippe
P
Gauthier-Rouvière
Cécile
C
Bloch-Gallego
Evelyne
E
D000818:Animals; D015820:Cadherins / Q000502:physiology*; D005154:Facial Nerve / Q000502:physiology; D020662:Guanine Nucleotide Exchange Factors / Q000502:physiology*; D051379:Mice; D009046:Motor Neurons / Q000502:physiology*; D009479:Neuropeptides / Q000502:physiology*; D009847:Olivary Nucleus / Q000502:physiology*; D010750:Phosphoproteins / Q000502:physiology*; D017346:Protein Serine-Threonine Kinases / Q000502:physiology*; D012249:Rhombencephalon / Q000196:embryology / Q000502:physiology*; D020744:rac GTP-Binding Proteins / Q000502:physiology*; D020830:rac1 GTP-Binding Protein
D015820:Cadherins; D020662:Guanine Nucleotide Exchange Factors; D009479:Neuropeptides; D010750:Phosphoproteins; C484602:Rac1 protein, mouse; C490975:Trio protein, mouse; C086960:osteoblast cadherin; D017346:Protein Serine-Threonine Kinases; D020744:rac GTP-Binding Proteins; D020830:rac1 GTP-Binding Protein