Chemosuppression of retinal axon growth by the mouse optic chiasm.
To determine whether diffusible guidance cues direct retinal axon growth and divergence at the optic chiasm, we cocultured mouse retinal and chiasm explants in collagen gels. The chiasm reduced retinal neurite lengths and numbers, but did not affect commissural or pontine neurite growth. This reduction in growth was equal for all retinal quadrants and occurred without reorienting the direction of neurite extension. The floor plate, another midline guidance locus, also suppressed retinal neurite outgrowth, whereas cortex or cerebellum explants did not. Growth suppression was not mediated by netrin-1, which instead enhanced retinal neurite extension. We propose that chemosuppression may be a general guidance mechanism that acts in intermediate targets to prime growth cones to perceive other, more specific cues.
Wang
L C
LC
Department of Pathology, College of Physicians and Surgeons, Columbia University, New York, New York 10032, USA.
Rachel
R A
RA
Marcus
R C
RC
Mason
C A
CA
D000818:Animals; D001369:Axons / Q000502:physiology*; D002450:Cell Communication / Q000502:physiology; D002452:Cell Count; D002455:Cell Division / Q000502:physiology; D002478:Cells, Cultured / Q000737:chemistry / Q000166:cytology; D003094:Collagen; D004027:Diencephalon / Q000737:chemistry / Q000166:cytology; D004058:Diffusion; D005260:Female; D005782:Gels; D006131:Growth Inhibitors / Q000502:physiology; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D009414:Nerve Growth Factors / Q000502:physiology; D000075388:Netrin-1; D009475:Neurons, Afferent / Q000737:chemistry / Q000166:cytology / Q000648:ultrastructure; D009897:Optic Chiasm / Q000737:chemistry* / Q000166:cytology*; D012160:Retina / Q000166:cytology*; D025521:Tumor Suppressor Proteins; D014795:Visual Pathways
D005782:Gels; D006131:Growth Inhibitors; D009414:Nerve Growth Factors; C000617353:Ntn1 protein, mouse; D025521:Tumor Suppressor Proteins; D000075388:Netrin-1; D003094:Collagen