title: Ten-m2 is required for the generation of binocular visual circuits.
abstract: Functional binocular vision requires that inputs arising from the two retinae are integrated and precisely organized within central visual areas. Previous studies have demonstrated an important role for one member of the Ten-m/Odz/teneurin family, Ten-m3, in the mapping of ipsilateral retinal projections. Here, we have identified a distinct role for another closely related family member, Ten-m2, in the formation of the ipsilateral projection in the mouse visual system. Ten-m2 expression was observed in the retina, dorsal lateral geniculate nucleus (dLGN), superior colliculus (SC), and primary visual cortex (V1) of the developing mouse. Anterograde and retrograde tracing experiments in Ten-m2 knock-out (KO) mice revealed a specific decrease in ipsilateral retinal ganglion cells projecting to dLGN and SC. This reduction was most prominent in regions corresponding to ventral retina. No change in the topography of ipsilateral or contralateral projections was observed. While expression of a critical ipsilateral fate determinant, Zic2, appeared unaltered, a notable reduction in one of its downstream targets, EphB1, was observed in ventral retina, suggesting that Ten-m2 may interact with this molecular pathway. Immunohistochemistry for c-fos, a neural activity marker, revealed that the area of V1 driven by ipsilateral inputs was reduced in KOs, while the ratio of ipsilateral-to-contralateral responses contributing to binocular activation during visually evoked potential recordings was also diminished. Finally, a novel two-alternative swim task revealed specific deficits associated with dorsal visual field. These data demonstrate a requirement for Ten-m2 in the establishment of ipsilateral projections, and thus the generation of binocular circuits, critical for mammalian visual function.
authors.affiliation: Discipline of Physiology, School of Medical Sciences and Bosch Institute, University of Sydney, New South Wales, 2006 Australia.
authors.forename: Timothy R
authors.initials: TR
authors.lastname: Young
authors.forename: Michael
authors.initials: M
authors.lastname: Bourke
authors.forename: Xiaohong
authors.initials: X
authors.lastname: Zhou
authors.forename: Toshitaka
authors.initials: T
authors.lastname: Oohashi
authors.forename: Atomu
authors.initials: A
authors.lastname: Sawatari
authors.forename: Reinhard
authors.initials: R
authors.lastname: Fässler
authors.forename: Catherine A
authors.initials: CA
authors.lastname: Leamey
mesh_terms: D000818:Animals; D023882:Dominance, Ocular / Q000502:physiology; D005260:Female; D005829:Geniculate Bodies / Q000166:cytology / Q000254:growth & development / Q000502:physiology; D008297:Male; D008565:Membrane Proteins / Q000235:genetics / Q000502:physiology*; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D009419:Nerve Tissue Proteins / Q000235:genetics / Q000502:physiology*; D036225:Receptor, EphB1 / Q000235:genetics / Q000502:physiology; D012165:Retinal Ganglion Cells / Q000502:physiology; D013477:Superior Colliculi / Q000166:cytology / Q000254:growth & development / Q000502:physiology; D015348:Vision, Binocular / Q000502:physiology*; D014793:Visual Cortex / Q000166:cytology / Q000254:growth & development / Q000502:physiology; D014795:Visual Pathways / Q000166:cytology / Q000254:growth & development* / Q000502:physiology*; D014796:Visual Perception / Q000502:physiology
chemical_list: D008565:Membrane Proteins; D009419:Nerve Tissue Proteins; C583794:Ten-m2 protein, mouse; C525233:Tenm3 protein, mouse; D036225:Receptor, EphB1