title: Changes in Musashi-1 subcellular localization correlate with cell cycle exit during postnatal retinal development.
abstract: RNA-binding proteins, and in particular, the Musashi genes, function as essential regulators of progenitor functioning in both the developing and adult organism. In this report, we characterize the differential subcellular distribution of Musashi-1 in cells engaged in either proliferating or differentiating contexts in the developing mouse retina, and in cultured Müller glia. During retinal cell differentiation, Musashi-1 immunoreactivity shifts from exclusively cytoplasmic in retinal progenitor cells, to predominantly nuclear localization in differentiating neurons. This nuclear shift is transient, with localization in the adult retina becoming predominantly perinuclear and cytoplasmic in Müller glia and photoreceptors. A correlation between cell cycle progression and subcellular distribution of Musashi-1 is observed in passageable, adult Müller glial cells in vitro. Furthermore, treatment of Müller cultures with neuron-promoting differentiation media induces asymmetric cytoplasmic Musashi-1 immunoreactivity in dividing daughter cells. The observed shifts in subcellular Musashi-1 localization are consistent with contrasting roles for Musashi-1 during cell proliferation and differentiation. These data provide evidence that nuclear, and cytoplasmic sequestering of Musashi-1 in retinal cells is context-specific, and may contribute to downstream functioning of Musashi-1.
authors.affiliation: Department of Biology, University of Victoria, Station CSC, PO Box 3020, Victoria, BC, Canada V8W3N5.
authors.forename: P E B
authors.initials: PE
authors.lastname: Nickerson
authors.forename: T
authors.initials: T
authors.lastname: Myers
authors.forename: D B
authors.initials: DB
authors.lastname: Clarke
authors.forename: R L
authors.initials: RL
authors.lastname: Chow
mesh_terms: D000818:Animals; D000831:Animals, Newborn; D002453:Cell Cycle / Q000502:physiology*; D002454:Cell Differentiation / Q000502:physiology; D002467:Cell Nucleus / Q000378:metabolism*; D049109:Cell Proliferation; D002478:Cells, Cultured; D003593:Cytoplasm / Q000378:metabolism*; D005260:Female; D019084:Fluorescent Antibody Technique, Indirect; D019394:Ki-67 Antigen / Q000378:metabolism; D051379:Mice; D008810:Mice, Inbred C57BL; D018613:Microscopy, Confocal; D009419:Nerve Tissue Proteins / Q000378:metabolism*; D009457:Neuroglia / Q000378:metabolism; D011247:Pregnancy; D016601:RNA-Binding Proteins / Q000378:metabolism*; D012160:Retina / Q000166:cytology / Q000196:embryology* / Q000254:growth & development; D055351:Retinal Neurons / Q000378:metabolism; D013234:Stem Cells / Q000378:metabolism; D014746:Vimentin / Q000378:metabolism
chemical_list: D019394:Ki-67 Antigen; C498355:Mki67 protein, mouse; C104786:Msi1h protein, mouse; D009419:Nerve Tissue Proteins; D016601:RNA-Binding Proteins; D014746:Vimentin