title: Müller glia reactivity follows retinal injury despite the absence of the glial fibrillary acidic protein gene in Xenopus.
abstract: Intermediate filament proteins are structural components of the cellular cytoskeleton with cell-type specific expression and function. Glial fibrillary acidic protein (GFAP) is a type III intermediate filament protein and is up-regulated in glia of the nervous system in response to injury and during neurodegenerative diseases. In the retina, GFAP levels are dramatically increased in Müller glia and are thought to play a role in the extensive structural changes resulting in Müller cell hypertrophy and glial scar formation. In spite of similar changes to the morphology of Xenopus Müller cells following injury, we found that Xenopus lack a gfap gene. Other type III intermediate filament proteins were, however, significantly induced following rod photoreceptor ablation and retinal ganglion cell axotomy. The recently available X. tropicalis and X. laevis genomes indicate a small deletion most likely resulted in the loss of the gfap gene during anuran evolution. Lastly, a survey of representative species from all three extant amphibian orders including the Anura (frogs, toads), Caudata (salamanders, newts), and Gymnophiona (caecilians) suggests that deletion of the gfap locus occurred in the ancestor of all Anura after its divergence from the Caudata ancestor around 290 million years ago. Our results demonstrate that extensive changes in Müller cell morphology following retinal injury do not require GFAP in Xenopus, and other type III intermediate filament proteins may be involved in the gliotic response.
authors.affiliation: Departments of Ophthalmology, Biochemistry & Molecular Biology, Neuroscience & Physiology, The Center for Vision Research and SUNY Eye Institute, Upstate Medical University, Syracuse 13210, NY, USA.
authors.forename: Reyna I
authors.initials: RI
authors.lastname: Martinez-De Luna
authors.affiliation: Departments of Ophthalmology, Biochemistry & Molecular Biology, Neuroscience & Physiology, The Center for Vision Research and SUNY Eye Institute, Upstate Medical University, Syracuse 13210, NY, USA.
authors.forename: Ray Y
authors.initials: RY
authors.lastname: Ku
authors.affiliation: Departments of Ophthalmology, Biochemistry & Molecular Biology, Neuroscience & Physiology, The Center for Vision Research and SUNY Eye Institute, Upstate Medical University, Syracuse 13210, NY, USA.
authors.forename: Alexandria M
authors.initials: AM
authors.lastname: Aruck
authors.affiliation: Departments of Ophthalmology, Biochemistry & Molecular Biology, Neuroscience & Physiology, The Center for Vision Research and SUNY Eye Institute, Upstate Medical University, Syracuse 13210, NY, USA.
authors.forename: Francesca
authors.initials: F
authors.lastname: Santiago
authors.affiliation: Departments of Ophthalmology, Biochemistry & Molecular Biology, Neuroscience & Physiology, The Center for Vision Research and SUNY Eye Institute, Upstate Medical University, Syracuse 13210, NY, USA.
authors.forename: Andrea S
authors.initials: AS
authors.lastname: Viczian
authors.affiliation: Department of Zoology & Physical Anthropology, Faculty of Biological Sciences, Complutense University, Madrid 28040, Spain.
authors.forename: Diego
authors.initials: D
authors.lastname: San Mauro
authors.affiliation: Departments of Ophthalmology, Biochemistry & Molecular Biology, Neuroscience & Physiology, The Center for Vision Research and SUNY Eye Institute, Upstate Medical University, Syracuse 13210, NY, USA. Electronic address: zuberm@upstate.edu.
authors.forename: Michael E
authors.initials: ME
authors.lastname: Zuber
mesh_terms: D000818:Animals; D030801:Animals, Genetically Modified; D001001:Anura / Q000235:genetics; D019771:Axotomy; D005075:Biological Evolution; D063928:Ependymoglial Cells / Q000473:pathology*; D005260:Female; D017353:Gene Deletion; D005904:Glial Fibrillary Acidic Protein / Q000235:genetics / Q000502:physiology; D005911:Gliosis / Q000473:pathology / Q000503:physiopathology*; D006801:Humans; D007381:Intermediate Filament Proteins / Q000502:physiology*; D007814:Larva; D008297:Male; D008795:Metronidazole / Q000633:toxicity; D051379:Mice; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism; D012160:Retina / Q000293:injuries*; D012165:Retinal Ganglion Cells / Q000473:pathology; D017948:Retinal Rod Photoreceptor Cells / Q000187:drug effects / Q000473:pathology; D013045:Species Specificity; D026801:Synteny; D014562:Caudata / Q000235:genetics; D014746:Vimentin / Q000502:physiology; D029867:Xenopus Proteins / Q000235:genetics / Q000502:physiology*; D014982:Xenopus laevis / Q000235:genetics / Q000254:growth & development / Q000502:physiology*
chemical_list: D005904:Glial Fibrillary Acidic Protein; D007381:Intermediate Filament Proteins; D011994:Recombinant Proteins; D014746:Vimentin; D029867:Xenopus Proteins; C528900:glial fibrillary astrocytic protein, mouse; D008795:Metronidazole