Alteration of Nrp1 signaling at different stages of olfactory neuron maturation promotes glomerular shifts along distinct axes in the olfactory bulb

Article Article scientifique Article Alteration of Nrp1 signaling at different stages of olfactory neuron maturation promotes glomerular shifts along distinct axes in the olfactory bulb eng 2016 author Assens Alexis 0000-0002-5194-8980 653599 author Dal Col Julien 515208 author Njoku Anthony 717594 author Dietschi Quentin 632833 author Kan Chenda author Feinstein Paul author Carleton Alan 676577 author Rodriguez Ivan 28183 3817-3825 10.1242/dev.138941 0950-1991 The building of the topographic map in the mammalian olfactory bulb is explained by a model based on two axes along which sensory neurons are guided: one dorso-ventral and the other antero-posterior. This latter axis relies on specific expression levels of Neuropilin 1 (Nrp1). To evaluate the role played by this receptor in this process, we used an in vivo genetic approach to decrease or suppress it in specific neuronal populations and at different time points during axonal targeting. We observed, in neurons that express either the M71 or the M72 odorant receptors, that the inactivation of Nrp1 leads to two distinct wiring alterations, whose incidence depends on the time at which Nrp1 expression is altered: first, a surprising dorsal shift of the M71 and M72 glomeruli that often fuse with their contralateral counterparts, and second, the formation of anteriorized glomeruli. The two phenotypes are partly recapitulated in mice lacking the Nrp1 ligand Semaphorin 3A (Sema3A), and in mice whose sensory neurons express a Nrp1 mutant unable to bind Sema3A. Finally, by using a mosaic conditional approach, we show that M71 axonal fibers can bypass the Nrp1 signals that define their target area, since they are hijacked and coalesce with Nrp1-deficient M71-expressing axons that target somewhere else. Together, these findings show drastically different axonal targeting outcomes dependent on the timing at which Nrp1/Sema3A signaling is altered. Dewey 590 Dewey 616.8 Swiss National Science Foundation Emergence and regulation of vomeronasal receptor genes in the mouse 149753 CH Project funding Swiss National Science Foundation Formyl peptide receptor-like receptors: an olfactory tool to identify pathogens? CH Project funding Swiss National Science Foundation Does ensemble decorrelation in the olfactory bulb predict odor discrimination behavior? 153410 CH Project funding Swiss National Science Foundation CR33I13_143723 and 31003A_153410 CH 44 Département de génétique et évolution 162 53 Département de neurosciences fondamentales 21A false 536 Groupe Carleton Alan (neurosciences fondamentales) 876 820 Groupe Rodriguez Development 143 c0f88085-8458-4dbf-bed7-b2c619b19217 Article (Published version) Public assensDevelopment2016.pdf 4055941 application/pdf Restricted 2017-09-11 openAccess Faculté des sciences / Section de biologie / Département de génétique et évolution Faculté de médecine / Section de médecine fondamentale / Département de neurosciences fondamentales

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Alteration of Nrp1 signaling at different stages of olfactory neuron maturation promotes glomerular shifts along distinct axes in the olfactory bulb	Development			2016	732	310

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Njoku, Anthony