title: Pax2 in the optic nerve of the goldfish, a model of continuous growth.
abstract: Pax2 is a well known transcription factor which participates in optic nerve development. It assures the correct arrival and package of the newly formed retinal axons and the adequate differentiation of the newly formed glial cells. Pax2 protein expression is continuous throughout adult life in the goldfish optic nerve. We have found two populations of astrocytes in the optic nerve: Pax2(+) and Pax2(-). Moreover, we have observed that the Pax2(+) astrocytes from the optic nerve head present differences in number and organization to those of the rest of the optic nerve. In the optic nerve head some Pax2(+) astrocytes, principally localized in the glia limitans, have thin GFAP(+) processes and weak cytokeratin and ZO1 immunolabeling. Several Pax2(+) astrocytes are in close association with the GFAP(+)/GS(+) Müller cell vitreal processes and with the growing Zn8(+) retinal ganglion cell axons. However, in the intraorbital segment, Pax2(+) astrocytes are more numerous and they have strongly cytokeratin(+)/ZO1(+) processes and form part of the reticular astrocytes and the glia limitans. We also found Pax2(-) astrocytes in both the optic nerve head and the intraorbital segment. In the intraorbital segment there are GS(+)/Pax2(-) cells which are absent from the optic nerve head. We propose that the maintenance of Pax2 protein expression in adult goldfish optic nerve could be related to the continuous addition of new ganglion cell axons and new glial cells.
authors.affiliation: Institute of Neuroscience of Castilla and León, Cell Biology, University of Salamanca, 37007 Salamanca, Spain.
authors.forename: Marta
authors.initials: M
authors.lastname: Parrilla
authors.forename: Concepción
authors.initials: C
authors.lastname: Lillo
authors.forename: M Javier
authors.initials: MJ
authors.lastname: Herrero-Turrion
authors.forename: Rosario
authors.initials: R
authors.lastname: Arévalo
authors.forename: Juan Manuel
authors.initials: JM
authors.lastname: Lara
authors.forename: José
authors.initials: J
authors.lastname: Aijón
authors.forename: Almudena
authors.initials: A
authors.lastname: Velasco
mesh_terms: D000818:Animals; D001253:Astrocytes / Q000378:metabolism*; D001369:Axons / Q000378:metabolism; D015153:Blotting, Western; D005904:Glial Fibrillary Acidic Protein / Q000378:metabolism; D006054:Goldfish; D007150:Immunohistochemistry; D008954:Models, Biological; D009416:Nerve Regeneration / Q000502:physiology*; D009898:Optic Disk / Q000166:cytology / Q000254:growth & development* / Q000378:metabolism; D051762:PAX2 Transcription Factor / Q000378:metabolism* / Q000502:physiology; D012165:Retinal Ganglion Cells / Q000378:metabolism / Q000502:physiology
chemical_list: D005904:Glial Fibrillary Acidic Protein; D051762:PAX2 Transcription Factor