title: Wlds protection distinguishes axon degeneration following injury from naturally occurring developmental pruning.
abstract: Axon pruning by degeneration remodels exuberant axonal connections and is widely required for the development of proper circuitry in the nervous system from insects to mammals. Developmental axon degeneration morphologically resembles injury-induced Wallerian degeneration, suggesting similar underlying mechanisms. As previously reported for mice, we show that Wlds protein substantially delays Wallerian degeneration in flies. Surprisingly, Wlds has no effect on naturally occurring developmental axon degeneration in flies or mice, although it protects against injury-induced degeneration of the same axons at the same developmental age. By contrast, the ubiquitin-proteasome system is intrinsically required for both developmental and injury-induced axon degeneration. We also show that the glial cell surface receptor Draper is required for efficient clearance of axon fragments during developmental axon degeneration, similar to its function in injury-induced degeneration. Thus, mechanistically, naturally occurring developmental axon pruning by degeneration and injury-induced axon degeneration differ significantly in early steps, but may converge onto a common execution pathway.
authors.affiliation: Howard Hughes Medical Institute, Department of Biological Sciences and Neurosciences Program, Stanford University, 385 Serra Mall, Stanford, California 94305, USA.
authors.forename: Eric D
authors.initials: ED
authors.lastname: Hoopfer
authors.forename: Todd
authors.initials: T
authors.lastname: McLaughlin
authors.forename: Ryan J
authors.initials: RJ
authors.lastname: Watts
authors.forename: Oren
authors.initials: O
authors.lastname: Schuldiner
authors.forename: Dennis D M
authors.initials: DD
authors.lastname: O'Leary
authors.forename: Liqun
authors.initials: L
authors.lastname: Luo
mesh_terms: D000818:Animals; D030801:Animals, Genetically Modified; D001369:Axons / Q000378:metabolism / Q000502:physiology* / Q000648:ultrastructure; D004330:Drosophila; D029721:Drosophila Proteins / Q000096:biosynthesis / Q000235:genetics / Q000502:physiology*; D018507:Gene Expression Regulation, Developmental / Q000502:physiology*; D051379:Mice; D008810:Mice, Inbred C57BL; D009419:Nerve Tissue Proteins / Q000096:biosynthesis / Q000235:genetics / Q000502:physiology*; D014855:Wallerian Degeneration / Q000235:genetics / Q000378:metabolism* / Q000473:pathology
chemical_list: D029721:Drosophila Proteins; D009419:Nerve Tissue Proteins; C442580:Wld protein, mouse