title: Extrinsic Repair of Injured Dendrites as a Paradigm for Regeneration by Fusion inCaenorhabditis elegans.
abstract: Injury triggers regeneration of axons and dendrites. Research has identified factors required for axonal regeneration outside the CNS, but little is known about regeneration triggered by dendrotomy. Here, we study neuronal plasticity triggered by dendrotomy and determine the fate of complex PVD arbors following laser surgery of dendrites. We find that severed primary dendrites grow toward each other and reconnect via branch fusion. Simultaneously, terminal branches lose self-avoidance and grow toward each other, meeting and fusing at the tips via an AFF-1-mediated process. Ectopic branch growth is identified as a step in the regeneration process required for bypassing the lesion site. Failure of reconnection to the severed dendrites results in degeneration of the distal end of the neuron. We discover pruning of excess branches via EFF-1 that acts to recover the original wild-type arborization pattern in a late stage of the process. In contrast, AFF-1 activity during dendritic auto-fusion is derived from the lateral seam cells and not autonomously from the PVD neuron. We propose a model in which AFF-1-vesicles derived from the epidermal seam cells fuse neuronal dendrites. Thus, EFF-1 and AFF-1 fusion proteins emerge as new players in neuronal arborization and maintenance of arbor connectivity following injury inCaenorhabditis elegansOur results demonstrate that there is a genetically determined multi-step pathway to repair broken dendrites in which EFF-1 and AFF-1 act on different steps of the pathway. EFF-1 is essential for dendritic pruning after injury and extrinsic AFF-1 mediates dendrite fusion to bypass injuries.
authors.affiliation: Department of Biology, Technion-Israel Institute of Technology, Haifa 32000, Israel.
authors.forename: Meital
authors.identifier: 0000-0001-9937-8326
authors.initials: M
authors.lastname: Oren-Suissa
authors.affiliation: Department of Biology, Technion-Israel Institute of Technology, Haifa 32000, Israel.
authors.forename: Tamar
authors.initials: T
authors.lastname: Gattegno
authors.affiliation: Department of Biology, Technion-Israel Institute of Technology, Haifa 32000, Israel.
authors.forename: Veronika
authors.initials: V
authors.lastname: Kravtsov
authors.affiliation: Department of Biology, Technion-Israel Institute of Technology, Haifa 32000, Israel podbilew@technion.ac.il.
authors.forename: Benjamin
authors.identifier: 0000-0002-0411-4182
authors.initials: B
authors.lastname: Podbilewicz
mesh_terms: D000818:Animals; D030801:Animals, Genetically Modified; D001369:Axons / Q000378:metabolism / Q000473:pathology; D017173:Caenorhabditis elegans / Q000235:genetics* / Q000254:growth & development; D029742:Caenorhabditis elegans Proteins / Q000235:genetics*; D003712:Dendrites / Q000235:genetics / Q000473:pathology; D008562:Membrane Glycoproteins / Q000235:genetics*; D009473:Neuronal Plasticity / Q000235:genetics; D012038:Regeneration / Q000235:genetics*; D011984:Sensory Receptor Cells / Q000378:metabolism
chemical_list: C520081:AFF-1 protein, C elegans; D029742:Caenorhabditis elegans Proteins; C470734:EFF-1 protein, C elegans; D008562:Membrane Glycoproteins
keywords: AFF-1; EFF-1; degeneration following dendrotomy; dendrite auto-fusion; regeneration of dendritic trees