title: Topographic restriction of TAG-1 expression in the developing retinotectal pathway and target dependent reexpression during axon regeneration.
abstract: TAG-1, a glycosylphosphatidyl inositol (GPI)-anchored protein of the immunoglobulin (Ig) superfamily, exhibits an unusual spatiotemporal expression pattern in the fish visual pathway. Using in situ hybridization and new antibodies (Abs) against fish TAG-1 we show that TAG-1 mRNA and anti-TAG-1 staining is restricted to nasal retinal ganglion cells (RGCs) in 24- to 72-h-old zebrafish embryos and in the adult, continuously growing goldfish retina. Anti-TAG-1 Abs selectively label nasal RGC axons in the nerve, optic tract, and tectum. Axotomized RGCs reexpress TAG-1, which occurs as late as 12 days after optic nerve lesion, when regenerating RGC axons arrive in the tectum, suggesting TAG-1 reexpression is target contact-dependent. Accordingly, TAG-1 reexpression ceases upon interruption of the regenerating projection by a second lesion. The topographic restriction of TAG-1 expression and its target dependency during regeneration suggests that TAG-1 might play a role in the retinotopic organization and restoration of the retinotectal pathway.
authors.affiliation: Department of Biology, University of Konstanz, Universitätsstrasse 10, Konstanz, 78467, Germany.
authors.forename: D M
authors.initials: DM
authors.lastname: Lang
authors.forename: J T
authors.initials: JT
authors.lastname: Warren
authors.forename: C
authors.initials: C
authors.lastname: Klisa
authors.forename: C A
authors.initials: CA
authors.lastname: Stuermer
mesh_terms: D000818:Animals; D001369:Axons / Q000737:chemistry / Q000502:physiology*; D015816:Cell Adhesion Molecules, Neuronal; D058969:Contactin 2; D018507:Gene Expression Regulation, Developmental; D006054:Goldfish; D008562:Membrane Glycoproteins / Q000032:analysis / Q000235:genetics*; D009416:Nerve Regeneration / Q000502:physiology*; D009900:Optic Nerve / Q000166:cytology / Q000196:embryology / Q000502:physiology; D020221:Optic Nerve Injuries; D012333:RNA, Messenger / Q000032:analysis; D012165:Retinal Ganglion Cells / Q000737:chemistry / Q000166:cytology / Q000502:physiology*; D013477:Superior Colliculi / Q000166:cytology / Q000196:embryology; D015027:Zebrafish
chemical_list: D015816:Cell Adhesion Molecules, Neuronal; D058969:Contactin 2; D008562:Membrane Glycoproteins; D012333:RNA, Messenger