title: Expression profiles suggest a role for Pax7 in the establishment of tectal polarity and map refinement.
abstract: The role for Pax7 in establishing tectal polarity and map refinement was authenticated by gene expression studies in vivo and in vitro. Throughout development (stages E2-E12 were examined) a rostral(low)-caudal(high) and dorsal(high)-ventral(low) Pax7 expression gradient was detected immunohistochemically in the chick optic tectum, indicating a role for Pax7 in establishing tectal polarity. Chick retino-recipient tectal cells positive for Pax7 also co-expressed ephrin-A2, a molecule involved in the establishment and refinement of the retinotopic map. In vitro, PAX7 up-regulated ephrin-A2 when transfected into undifferentiated P19 cells; cells became negative for both Pax7 and ephrin-A2 protein following treatment with anti-sense oligonucleotides. These results suggest that in addition to being involved in the early establishment of tectal polarity, Pax7 plays a later role in retino-tectal map formation and refinement.
authors.affiliation: School of Surgery and Pathology, University of Western Australia, Perth, Western Australia, Australia.
authors.forename: Meghan
authors.initials: M
authors.lastname: Thomas
authors.forename: Stan
authors.initials: S
authors.lastname: Lazic
authors.forename: Lyn
authors.initials: L
authors.lastname: Beazley
authors.forename: Melanie
authors.initials: M
authors.lastname: Ziman
mesh_terms: D000818:Animals; D019521:Body Patterning / Q000235:genetics*; D002450:Cell Communication / Q000235:genetics; D002454:Cell Differentiation / Q000235:genetics*; D016764:Cell Polarity / Q000235:genetics; D002478:Cells, Cultured; D002642:Chick Embryo; D003463:Cues; D036383:Ephrin-A2 / Q000235:genetics / Q000378:metabolism; D018507:Gene Expression Regulation, Developmental / Q000235:genetics; D020439:Growth Cones / Q000378:metabolism / Q000648:ultrastructure; D018398:Homeodomain Proteins / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D051379:Mice; D009474:Neurons / Q000166:cytology / Q000378:metabolism; D016376:Oligonucleotides, Antisense / Q000494:pharmacology; D051763:PAX7 Transcription Factor; D012160:Retina / Q000166:cytology / Q000196:embryology / Q000378:metabolism; D013477:Superior Colliculi / Q000166:cytology / Q000196:embryology / Q000378:metabolism*; D014162:Transfection; D015854:Up-Regulation / Q000235:genetics; D014795:Visual Pathways / Q000166:cytology / Q000196:embryology / Q000378:metabolism*
chemical_list: D036383:Ephrin-A2; D018398:Homeodomain Proteins; D016376:Oligonucleotides, Antisense; D051763:PAX7 Transcription Factor; C497322:Pax7 protein, mouse