title: Revisiting the neuronal localization and trafficking of CLN3 in juvenile neuronal ceroid lipofuscinosis.
abstract: Juvenile neuronal ceroid lipofuscinosis, the most common neurodegenerative disease affecting children, is caused by mutations of the CLN3 gene encoding CLN3, a transmembrane protein with so far undefined function. The embryonic expression of the gene has not been studied in detail before. Moreover, the protein CLN3 was mostly localized on the subcellular level to lysosomes but the exclusiveness is still under debate. Here, we analyze the expression pattern of murine CLN3 at different developmental stages by in situ hybridizations. We observe expression maxima in the developing thalamus and cerebral cortex and outside of the central nervous system in the gastrointestinal tract and other peripheral organs. In differentiated primary neurons, the protein CLN3 shows mainly a somatodendritic localization. In primary neurons, we thoroughly revisit the subcellular localization of CLN3 and find a predominant localization in late endosomal-lysosomal compartments. Moreover, we expressed the major mutant form of CLN3 - CLN3deltaExon7/8 - in neurons and demonstrate that it is retained in the endoplasmatic reticulum. Time-lapse microscopy analysis of neurons revealed co-trafficking of CLN3 with the late endosomal marker Rab7, but not with the early endosomal marker Rab5. Furthermore, a constitutive active mutant of Rab7 traps CLN3 in enlarged endosomes. Our subcellular localization study in neurons refines the localization and subcellular targeting of CLN3 to late endosomal-lysosomal compartments and provides information on the velocity of CLN3 in living neurons which has not been investigated before.
authors.affiliation: Institute for Molecular and Cellular Cognition, Center for Molecular Neurobiology Hamburg, University Medical Center Hamburg-Eppendorf, Hamburg, Germany.
authors.forename: Sandra
authors.initials: S
authors.lastname: Oetjen
authors.affiliation: Institute for Molecular and Cellular Cognition, Center for Molecular Neurobiology Hamburg, University Medical Center Hamburg-Eppendorf, Hamburg, Germany.
authors.forename: Dietmar
authors.initials: D
authors.lastname: Kuhl
authors.affiliation: Institute for Molecular and Cellular Cognition, Center for Molecular Neurobiology Hamburg, University Medical Center Hamburg-Eppendorf, Hamburg, Germany. guido.hermey@zmnh.uni-hamburg.de.
authors.forename: Guido
authors.initials: G
authors.lastname: Hermey
mesh_terms: D000818:Animals; D002454:Cell Differentiation; D002540:Cerebral Cortex / Q000378:metabolism; D003713:Dendritic Cells / Q000378:metabolism; D004721:Endoplasmic Reticulum / Q000378:metabolism; D011992:Endosomes / Q000378:metabolism / Q000648:ultrastructure; D005260:Female; D008247:Lysosomes / Q000201:enzymology; D008562:Membrane Glycoproteins / Q000235:genetics / Q000378:metabolism*; D051379:Mice; D008810:Mice, Inbred C57BL; D018832:Molecular Chaperones / Q000235:genetics / Q000378:metabolism*; D009154:Mutation / Q000235:genetics; D009472:Neuronal Ceroid-Lipofuscinoses / Q000235:genetics / Q000378:metabolism*; D011247:Pregnancy; D013347:Subcellular Fractions / Q000378:metabolism; D013788:Thalamus / Q000378:metabolism; D020691:rab GTP-Binding Proteins / Q000378:metabolism; D000090802:rab7 GTP-Binding Proteins
chemical_list: C102229:CLN3 protein, mouse; D008562:Membrane Glycoproteins; D018832:Molecular Chaperones; D000090802:rab7 GTP-Binding Proteins; C000716465:rab7 GTP-binding proteins, mouse; D020691:rab GTP-Binding Proteins
keywords: CLN3; Rab7; intracellular transport; juvenile neuronal ceroid lipofuscinosis; late endosome; lysosome