title: A simple method for 3D analysis of immunolabeled axonal tracts in a transparent nervous system.
abstract: Clearing techniques have been developed to transparentize mouse brains, thereby preserving 3D structure, but their complexity has limited their use. Here, we show that immunolabeling of axonal tracts followed by optical clearing with solvents (3DISCO) and light-sheet microscopy reveals brain connectivity in mouse embryos and postnatal brains. We show that the Robo3 receptor is selectively expressed by medial habenula axons forming the fasciculus retroflexus (FR) and analyzed the development of this commissural tract in mutants of the Slit/Robo and DCC/Netrin pathways. Netrin-1 and DCC are required to attract FR axons to the midline, but the two mutants exhibit specific and heterogeneous axon guidance defects. Moreover, floor-plate-specific deletion of Slit ligands with a conditional Slit2 allele perturbs not only midline crossing by FR axons but also their anteroposterior distribution. In conclusion, this method represents a unique and powerful imaging tool to study axonal connectivity in mutant mice.
authors.affiliation: Sorbonne Universités, UPMC Université Paris 06, UMRS 968, Institut de la Vision, Paris 75012, France; INSERM, UMRS 968, Institut de la Vision, Paris 75012, France; CNRS, UMR 7210, Paris 75012, France.
authors.forename: Morgane
authors.initials: M
authors.lastname: Belle
authors.affiliation: Sorbonne Universités, UPMC Université Paris 06, UMRS 968, Institut de la Vision, Paris 75012, France; INSERM, UMRS 968, Institut de la Vision, Paris 75012, France; CNRS, UMR 7210, Paris 75012, France.
authors.forename: David
authors.initials: D
authors.lastname: Godefroy
authors.affiliation: Sorbonne Universités, UPMC Université Paris 06, UMRS 968, Institut de la Vision, Paris 75012, France; INSERM, UMRS 968, Institut de la Vision, Paris 75012, France; CNRS, UMR 7210, Paris 75012, France.
authors.forename: Chloé
authors.initials: C
authors.lastname: Dominici
authors.affiliation: Sorbonne Universités, UPMC Université Paris 06, UMRS 968, Institut de la Vision, Paris 75012, France; INSERM, UMRS 968, Institut de la Vision, Paris 75012, France; CNRS, UMR 7210, Paris 75012, France.
authors.forename: Céline
authors.initials: C
authors.lastname: Heitz-Marchaland
authors.affiliation: Sorbonne Universités, UPMC Université Paris 06, UMRS 968, Institut de la Vision, Paris 75012, France; INSERM, UMRS 968, Institut de la Vision, Paris 75012, France; CNRS, UMR 7210, Paris 75012, France.
authors.forename: Pavol
authors.initials: P
authors.lastname: Zelina
authors.affiliation: Deutsches Zentrum für Neurodegenerative Erkrankungen (DZNE), Axon Growth and Regeneration, Ludwig-Erhard-Allee 2, 53175 Bonn, Germany.
authors.forename: Farida
authors.initials: F
authors.lastname: Hellal
authors.affiliation: Deutsches Zentrum für Neurodegenerative Erkrankungen (DZNE), Axon Growth and Regeneration, Ludwig-Erhard-Allee 2, 53175 Bonn, Germany.
authors.forename: Frank
authors.initials: F
authors.lastname: Bradke
authors.affiliation: Sorbonne Universités, UPMC Université Paris 06, UMRS 968, Institut de la Vision, Paris 75012, France; INSERM, UMRS 968, Institut de la Vision, Paris 75012, France; CNRS, UMR 7210, Paris 75012, France. Electronic address: alain.chedotal@inserm.fr.
authors.forename: Alain
authors.initials: A
authors.lastname: Chédotal
mesh_terms: D000818:Animals; D001369:Axons / Q000378:metabolism*; D015415:Biomarkers / Q000378:metabolism; D001921:Brain / Q000378:metabolism*; D000075389:DCC Receptor; D004622:Embryo, Mammalian / Q000378:metabolism; D021621:Imaging, Three-Dimensional / Q000379:methods*; D008565:Membrane Proteins / Q000378:metabolism; D018345:Mice, Knockout; D009154:Mutation; D009414:Nerve Growth Factors / Q000378:metabolism; D009419:Nerve Tissue Proteins / Q000378:metabolism; D000075388:Netrin-1; D011956:Receptors, Cell Surface / Q000172:deficiency / Q000378:metabolism; D013194:Staining and Labeling; D025521:Tumor Suppressor Proteins / Q000172:deficiency / Q000378:metabolism; D000097905:Roundabout Proteins
chemical_list: D015415:Biomarkers; D000075389:DCC Receptor; D008565:Membrane Proteins; D009414:Nerve Growth Factors; D009419:Nerve Tissue Proteins; D000075388:Netrin-1; D011956:Receptors, Cell Surface; D025521:Tumor Suppressor Proteins; C501910:Dcc protein, mouse; C000617353:Ntn1 protein, mouse; C118348:Robo3 protein, mouse; D000097905:Roundabout Proteins