RESEARCH ARTICLE Correct setup of the substantia nigra requires Reelin-mediated fast, laterally- directed migration of dopaminergic neurons Ankita Ravi Vaswani1, Beatrice Weykopf2†, Cathleen Hagemann1, Hans-Ulrich Fried3, Oliver Bru¨ stle2, Sandra Blaess1* 1Neurodevelopmental Genetics, Institute of Reconstructive Neurobiology, University of Bonn School of Medicine & University Hospital Bonn, Bonn, Germany; 2Institute of Reconstructive Neurobiology, University of Bonn School of Medicine & University Hospital Bonn, Bonn, Germany; 3Light Microscope Facility, German Center for Neurodegenerative Diseases, Bonn, Germany Abstract Midbrain dopaminergic (mDA) neurons migrate to form the laterally-located substantia nigra pars compacta (SN) and medially-located ventral tegmental area (VTA), but little is known about the underlying cellular and molecular processes. Here we visualize the dynamic cell morphologies of tangentially migrating SN-mDA neurons in 3D and identify two distinct migration modes. Slow migration is the default mode in SN-mDA neurons, while fast, laterally-directed *For correspondence: migration occurs infrequently and is strongly associated with bipolar cell morphology. Tangential
[email protected] migration of SN-mDA neurons is altered in absence of Reelin signaling, but it is unclear whether Reelin acts directly on migrating SN-mDA neurons and how it affects their cell morphology and † Present address: Precision migratory behavior. By specifically inactivating Reelin signaling in mDA neurons we demonstrate its Neurology Program & Advanced direct role in SN-mDA tangential migration. Reelin promotes laterally-biased movements in mDA Center for Parkinson’s Disease neurons during their slow migration mode, stabilizes leading process morphology and increases the Research, Harvard Medical School and Brigham & Women’s probability of fast, laterally-directed migration.