Polleux F, Ince-Dunn G, Ghosh A: Transcriptional regulation of vertebrate axon guidance and synapse formation.Lamballe F, Genestine M, Caruso N, Arce V, Richelme S, Helmbacher F, Maina F: Pool-specific regulation of motor neuron survival by neurotrophic support. Pawson T, Scott JD: Signaling through scaffold, anchoring, and adaptor proteins.10.20. Science 1997, 278:2075?080. 2. Acknowledgements We thank Chris Henderson for invaluable intellectual support; Ruediger Klein for supporting this study in its early stages and for valuable comments on the manuscript, and former members of his laboratory for insightful discussion; Disposable Plastic Ware Elise Arbeille for help with ISHs of spinal cord sections; Sylvie Richelme for technical help; Virginia Girod-David and Leo Jullien for excellent help with mouse husbandry at the IBDM; and Angela Zimmermann for comments on the manuscript. Final approval was given by all authors.23.

Encinas M, Tansey MG, Tsui-Pierchala BA, Comella JX, SN-38custom synthesis Milbrandt J, Johnson EM Jr: c-Src is required for glial cell line-derived neurotrophic factor (GDNF) family ligand-mediated neuronal survival via a phosphatidylinositol-3 kinase (PI-3 K)-dependent pathway. FH, NC, BH, FL and VA-G performed the experiments. Polleux F, Ince-Dunn G, Ghosh A: Transcriptional regulation of vertebrate axon guidance and synapse formation. Tallquist MD, Klinghoffer RA, Heuchel R, Mueting-Nelsen PF, Corrin PD, Heldin CH, J. Authors' contributions FM and FH are co-senior authors. Postigo A, Calella AM, Fritzsch B, Knipper M, Katz D, Eilers A, Schimmang T, Lewin GR, Klein R, Minichiello L: Distinct requirements for TrkB and TrkC signaling in target innervation by sensory neurons. Shneider NA, Brown MN, Smith CA, Pickel J, Alvarez FJ: Gamma motor neurons express distinct genetic markers at birth and require muscle spindle-derived GDNF for postnatal survival. Received: 1 July 2014 Accepted: 4 July4. Kanning KC, Kaplan A, Henderson CE: Motor neuron diversity in development and disease.. J Neurosci 2011, 31:11144?1158.15.20.12. Final approval was given by all authors.5.11. Pawson T, Scott JD: Signaling through scaffold, anchoring, and adaptor proteins. 3. FH wrote the manuscript with proofreading by FM.Lamballe F, Genestine M, Caruso N,

Arce V, Richelme S, Helmbacher F, Maina F: Pool-specific regulation of motor neuron survival by neurotrophic support. Work in the Maina lab by FM was supported by FRM, AFM, FdF, ARC, Fondation Bettencourt-Schueller and INCa (Institut National du Cancer). 7.22.14. Acknowledgements We thank Chris Henderson for invaluable intellectual support; Ruediger Klein for supporting this study in its early stages and for valuable comments on the manuscript, and former members of his laboratory for insightful discussion;

Elise Arbeille for help with ISHs of spinal cord sections; Sylvie Richelme for technical help; Virginia Girod-David and Leo Jullien for excellent help with mouse husbandry at the IBDM; and Angela Zimmermann for comments on the manuscript.16.Ing interests. Neural Dev 2009, 4:42. Genes Dev 2002, 16:633?45. Curr Top Dev Biol 2009, 87:119?48.17.10. FH and FM conceived, designed and directed the study, and analysed and interpreted the data. Dasen JS: Transcriptional networks in the early development of sensory-motor circuits.19. Nat Rev Neurosci 2007, 8:331?40. Medina DL, Sciarretta C, Calella AM, Von Bohlen Und Halbach O, Unsicker K, Minichiello L: TrkB regulates neocortex formation through the Shc/PLCmediated control of neuronal migration. 2.23.21.18. Annu Rev Neurosci 2010, 33:409?40. Work in the Helmbacher laboratory was supported by funds from the CNRS (ATIP grant), FRM (Fondation pour la Recherche M icale, Equipe FRM 2007), AFM (Association Fran ise contre les Myopathies), FdF (Fondation de France), ARC (Association pour la Recherche contre le Cancer) and ANR (Agence Nationale de la Recherche, ANR Neuro 2007). J Neurosci 2001, 21:1464?472.

The contributions of the Region Provence Alpes C es d'Azur Lab Consumables and Aix-Marseille Universit?for the IBDM animal facility, and of the France-BioImaging/PICsL infrastructure (ANR-10-INSB-04-01) for the imaging facility are also acknowledged. Science 1997, 278:2075?080.13.9.8. EMBO J 2004, 23:3803?814.6.References 1