Objective The mature nervous system is an intricate network in which neurons are connected to specific partners. The construction of the network requires directed growth of axons towards their appropriate targets during development and during neuronal regeneration after a lesion. Axons must navigate through a complex environment where they are guided by a combination of attractive and repulsive molecules. Cellular second messengers, particularly calcium and cyclic nucleotides – cyclic adenosine monophosphate (cAMP) and cyclic guanosine monophosphate (cGMP) – are critical for responses to guidance molecules and axonal pathfinding. Recently, the temporal structure of calcium signals has been shown to have a key role in regulating growth cone behaviors, but the temporal components of cAMP and cGMP signals are largely unknown. The present project proposes to investigate the involvement of second messengers during the midline crossing of spinal commissural axons in vivo. We will first identify the crucial second messengers for the guidance of those axons in the Xenopus spinal cord in vivo. Second, we will use newly improved cyclic nucleotide FRET probes and fluorescent calcium sensors to determine the temporal dynamics of cAMP, cGMP and calcium signaling (the frequency of transients and sustained variations in their intracellular concentrations) in vivo in the growth cones of spinal commissural interneurons. We will then investigate the respective roles of temporally restricted and sustained variations of second messengers in the guidance of commissural axons in vivo, by imposing different frequencies of transient or sustained perturbations of cAMP, cGMP and calcium. Finally, we will investigate the interdependence of these signaling pathways by imaging one second messengers while manipulating another. These studies will substantially advance our understanding of signaling necessary for axonal pathfinding by spinal cord neurons. Fields of science natural sciencesbiological sciencesneurobiologynatural scienceschemical sciencesinorganic chemistryalkaline earth metalsengineering and technologyelectrical engineering, electronic engineering, information engineeringelectronic engineeringsensorsnatural sciencesbiological sciencesgeneticsnucleotides Keywords FRET axon guidance cAMP calcium developmental biology in vivo imaging neurobiology spinal cord Programme(s) FP7-PEOPLE - Specific programme "People" implementing the Seventh Framework Programme of the European Community for research, technological development and demonstration activities (2007 to 2013) Topic(s) PEOPLE-2007-4-1.IOF - Marie Curie Action: "International Outgoing Fellowships for Career Development" Call for proposal FP7-PEOPLE-2007-4-1-IOF See other projects for this call Funding Scheme MC-IOF - International Outgoing Fellowships (IOF) Coordinator INSTITUT NATIONAL DE LA SANTE ET DE LA RECHERCHE MEDICALE EU contribution € 239 169,49 Address RUE DE TOLBIAC 101 75654 Paris France See on map Region Ile-de-France Ile-de-France Paris Activity type Research Organisations Administrative Contact Mihaja Auguste (Ms.) Links Contact the organisation Opens in new window Website Opens in new window Total cost No data