title: Four-dimensional analysis of nucleogenesis of the pontine nucleus in the hindbrain.
abstract: Nuclei in the central nervous system are 3D aggregates of neurons that have common physiological properties, functionalities, and connectivities. To form specific nuclei, neurons migrate from their birthplace towards the presumptive nuclear region where they change their dynamics to aggregate and rearrange into a distinct 3D structure, a process that we term nucleogenesis. Nuclei, together with the laminar structure, form the basic cytoarchitectonic unit for information processing. However, in contrast to much-studied laminar structures, the neuronal dynamics that contribute to the aggregation process to form nuclei are poorly understood. Here, we analyze nucleogenesis by observing the mouse precerebellar pontine nucleus (PN), and provide the first 4D view of nucleogenesis by tracking neuronal behaviors along the three spatial axes over time. Early- and late-born PN neurons were labeled by in utero electroporation and their behaviors on cultured brain slices were recorded by time-lapse imaging. We find that when PN neurons migrate medially into the nuclear region, many of them switch to migrate radially and laterally, to populate the dorsal and lateral PN regions, respectively. The tendency to switch to radial migration is much less in later-born neurons, whereas that to switch to lateral migration is comparable between the two groups. In contrast to the radial and mediolateral axes, very few PN neurons switch to migrate rostrocaudally. These results could thus provide a framework for understanding the mechanisms that regulate this complex yet important process.
authors: Graduate School of Frontier Biosciences, Osaka University, Suita, Osaka 560-8531, Japan.
authors: Masaki
authors: M
authors: Shinohara
authors: Yan
authors: Y
authors: Zhu
authors: Fujio
authors: F
authors: Murakami
mesh_terms: D000818:Animals; D000831:Animals, Newborn; D001973:Bromodeoxyuridine / Q000378:metabolism; D002465:Cell Movement; D002467:Cell Nucleus / Q000502:physiology*; D018274:Electroporation; D004622:Embryo, Mammalian; D005260:Female; D049452:Green Fluorescent Proteins / Q000235:genetics / Q000378:metabolism; D051379:Mice; D008813:Mice, Inbred ICR; D055495:Neurogenesis / Q000502:physiology; D009474:Neurons / Q000166:cytology* / Q000502:physiology*; D011149:Pons / Q000166:cytology* / Q000196:embryology / Q000254:growth & development; D011247:Pregnancy; D013997:Time Factors; D059008:Time-Lapse Imaging
chemical_list: D049452:Green Fluorescent Proteins; D001973:Bromodeoxyuridine
keywords: neuronal migration; nuclei formation; pontine nucleus; time-lapse imaging