title: Partial regeneration and long-term survival of rat retinal ganglion cells after optic nerve crush is accompanied by altered expression, phosphorylation and distribution of cytoskeletal proteins.
abstract: In a screen to identify genes that are expressed differentially in the retina after partial optic nerve crush, we identified MAP1B as an up-regulated transcript. Western blot analysis of inner retina protein preparations confirmed changes in the protein composition of the microtubule-associated cytoskeleton of crushed vs. uncrushed nerve. MAP1B immunoreactivity and transcript levels were elevated for two weeks after crush. Immunostaining and Western blots with monoclonal antibodies directed against developmentally regulated phosphorylation sites on MAP1B revealed a gradient of MAP1B phosphorylation from the proximal optic nerve stump to the soma of retinal ganglion cells. Most interestingly, using antibodies directed against developmentally regulated phosphorylation sites on MAP1B, we observed that a significant number of crushed optic nerve axons develop MAP1B-immunopositive growth cones, which cross the crush site and migrate along the distal nerve fragment. In parallel, an abnormal distribution of highly phosphorylated neurofilament protein (pNF-H) in the cell soma and dendrites of presumably axotomized retinal ganglion cells was observed following partial nerve crush. This redistribution is present for the period between day 7 and 28 postcrush and is not seen in cells that stay connected to the superior colliculus. Axotomized ganglion cells, which contain pNF-H in soma and dendrites appear to have been disconnected from the colliculus at an early stage but survive axonal trauma for long periods.
authors.affiliation: AG Molecular Mechanisms of Plasticity, Department of Neurochemistry/Molecular Biology, Leibniz Institute for Neurobiology, Magdeburg, Germany.
authors.forename: Daniela C
authors.initials: DC
authors.lastname: Dieterich
authors.forename: Niraj
authors.initials: N
authors.lastname: Trivedi
authors.forename: Ralf
authors.initials: R
authors.lastname: Engelmann
authors.forename: Eckart D
authors.initials: ED
authors.lastname: Gundelfinger
authors.forename: Phillip R
authors.initials: PR
authors.lastname: Gordon-Weeks
authors.forename: Michael R
authors.initials: MR
authors.lastname: Kreutz
mesh_terms: D000818:Animals; D000918:Antibody Specificity / Q000276:immunology; D002451:Cell Compartmentation / Q000502:physiology; D002470:Cell Survival / Q000502:physiology*; D003598:Cytoskeletal Proteins / Q000378:metabolism*; D003712:Dendrites / Q000378:metabolism / Q000648:ultrastructure; D005456:Fluorescent Dyes; D005786:Gene Expression Regulation / Q000502:physiology; D020439:Growth Cones / Q000378:metabolism* / Q000648:ultrastructure; D007150:Immunohistochemistry; D008297:Male; D008869:Microtubule-Associated Proteins / Q000235:genetics / Q000378:metabolism; D009410:Nerve Degeneration / Q000378:metabolism* / Q000503:physiopathology; D009416:Nerve Regeneration / Q000502:physiology*; D016900:Neurofilament Proteins / Q000378:metabolism; D020221:Optic Nerve Injuries / Q000378:metabolism* / Q000503:physiopathology; D010766:Phosphorylation; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D012165:Retinal Ganglion Cells / Q000166:cytology / Q000378:metabolism*; D015854:Up-Regulation / Q000502:physiology
chemical_list: D003598:Cytoskeletal Proteins; D005456:Fluorescent Dyes; D008869:Microtubule-Associated Proteins; D016900:Neurofilament Proteins; D012333:RNA, Messenger; C085284:microtubule-associated protein 1B; C051774:neurofilament protein H