Semaphorin3D guides retinal axons along the dorsoventral axis of the tectum.
We examined the role of Sema3D, a semaphorin of previously unknown function, in guiding retinal ganglion cell (RGC) axons to the optic tectum in the developing zebrafish. Sema3D is expressed more strongly in the ventral versus dorsal tectum, suggesting that it may participate in guiding RGC axons along the dorsoventral axis of the tectum. Ubiquitous misexpression of Sema3D in transgenic zebrafish inhibits ventral but not dorsal RGC axon growth. In addition, ventral RGC axons avoid or stop at individual cells misexpressing Sema3D along their pathway. Sema3D ubiquitous misexpression at later stages also causes ventral RGC axon arbors to spread more widely along the dorsoventral axis of the tectum. Knock-down of Sema3D with morpholino antisense causes ventral RGC axons to extend aberrantly into the ventral tectum. These results suggest that Sema3D in the ventral tectum normally acts to inhibit ventral RGCs from extending into ventral tectum, ensuring their correct innervation of dorsal tectum.
Liu
Yan
Y
Department of Zoology and Anatomy, University of Wisconsin, Madison, Wisconsin 53706, USA.
Berndt
Jason
J
Su
Fengyun
F
Tawarayama
Hiroshi
H
Shoji
Wataru
W
Kuwada
John Y
JY
Halloran
Mary C
MC
D000818:Animals; D016375:Antisense Elements (Genetics); D001369:Axons / Q000648:ultrastructure*; D002352:Carrier Proteins / Q000235:genetics / Q000502:physiology*; D009419:Nerve Tissue Proteins / Q000235:genetics / Q000502:physiology*; D039921:Neuropilins / Q000378:metabolism; D030781:Organisms, Genetically Modified; D012160:Retina / Q000196:embryology*; D012165:Retinal Ganglion Cells / Q000166:cytology*; D039961:Semaphorins / Q000235:genetics / Q000502:physiology*; D013477:Superior Colliculi / Q000166:cytology* / Q000196:embryology / Q000378:metabolism; D014795:Visual Pathways / Q000166:cytology / Q000196:embryology; D015027:Zebrafish / Q000033:anatomy & histology / Q000196:embryology / Q000235:genetics
D016375:Antisense Elements (Genetics); D002352:Carrier Proteins; D009419:Nerve Tissue Proteins; D039921:Neuropilins; D039961:Semaphorins