Met signaling is required for recruitment of motor neurons to PEA3-positive motor pools.
Motor neurons in the spinal cord are grouped into motor pools, each of which innervates a single muscle. The ETS transcription factor PEA3 is a marker of a few such motor pools. Here, we show that pea3 is first induced by GDNF in a caudal subset of the motor neurons that will constitute the pea3+ population. Expansion of the pea3 domain subsequently occurs by recruitment of neurons from more anterior segments. Signaling by Met, the HGF receptor, is required for the rostral expansion of the pea3 domain, while the onset of pea3 expression is independent of met function. met expression is observed in pioneer neurons but does not precede that of pea3 in recruited neurons. We provide genetic evidence for a non-cell-autonomous function of met during the recruitment process. We propose the presence of a relay mechanism allowing cells induced by peripheral signals to recruit more anterior neurons to adopt the same motor pool-related phenotype.
Helmbacher
Françoise
F
Max Planck Institute of Neurobiology, am Klopferspitz 18a, 82152 Martinsried, Germany.
Dessaud
Eric
E
Arber
Silvia
S
deLapeyrière
Odile
O
Henderson
Christopher E
CE
Klein
Rüdiger
R
Maina
Flavio
F
D000818:Animals; D019521:Body Patterning / Q000502:physiology*; D004622:Embryo, Mammalian; D018507:Gene Expression Regulation, Developmental; D051100:Glial Cell Line-Derived Neurotrophic Factor; D007150:Immunohistochemistry; D017403:In Situ Hybridization; D051379:Mice; D008817:Mice, Mutant Strains; D009046:Motor Neurons / Q000502:physiology*; D018482:Muscle, Skeletal / Q000294:innervation; D009154:Mutation; D009414:Nerve Growth Factors / Q000378:metabolism; D009924:Organ Culture Techniques; D019859:Proto-Oncogene Proteins c-met / Q000172:deficiency / Q000235:genetics / Q000378:metabolism*; D015398:Signal Transduction / Q000502:physiology; D013116:Spinal Cord / Q000166:cytology / Q000196:embryology*; D014157:Transcription Factors / Q000378:metabolism*
C495040:Gdnf protein, mouse; D051100:Glial Cell Line-Derived Neurotrophic Factor; D009414:Nerve Growth Factors; D014157:Transcription Factors; C065788:transcription factor PEA3; D019859:Proto-Oncogene Proteins c-met