GSBS Student Publications

Title

Sonic hedgehog has a dual effect on the growth of retinal ganglion axons depending on its concentration

UMMS Affiliation

Graduate School of Biomedical Sciences; Department of Cell Biology; Department of Medicine, Division of Endocrinology and Metabolism

Date

4-1-2005

Document Type

Article

Medical Subject Headings

Age Factors; Animals; Axons; Cells, Cultured; Chick Embryo; Coculture Techniques; Dose-Response Relationship, Drug; Drug Interactions; Fluorescent Antibody Technique; Gene Expression Regulation, Developmental; Green Fluorescent Proteins; Growth Cones; Hedgehog Proteins; In Situ Hybridization; Neural Inhibition; Optic Disk; Organ Culture Techniques; RNA, Messenger; Recombinant Proteins; Retina; Retinal Ganglion Cells; Time Factors; Trans-Activators; Veratrum Alkaloids

Disciplines

Life Sciences | Medicine and Health Sciences

Abstract

The stereotypical projection of retinal ganglion cell (RGC) axons to the optic disc has served as a good model system for studying axon guidance. By both in vitro and in vivo experiments, we show that a secreted molecule, Sonic hedgehog (Shh), may play a critical role in the process. It is expressed in a dynamic pattern in the ganglion cell layer with a relatively higher expression in the center of the retina. Through gel culture and stripe assays, we show that Shh has a dual effect on RGC axonal growth, acting as a positive factor at low concentrations and a negative factor at high concentrations. Results from time-lapse video microscopic and stripe assay experiments further suggest that the effects of Shh on axons are not likely attributable to indirect transcriptional regulation by Shh. Overexpression of Shh protein or inhibition of Shh function inside the retina resulted in a complete loss of centrally directed projection of RGC axons, suggesting that precise regulation of Shh level inside the retina is critical for the projection of RGC axons to the optic disc.

Rights and Permissions

Citation: J Neurosci. 2005 Mar 30;25(13):3432-41. Link to article on publisher's site

DOI of Published Version

10.1523/JNEUROSCI.4938-04.2005

Related Resources

Link to article in PubMed

Journal Title

The Journal of neuroscience : the official journal of the Society for Neuroscience

PubMed ID

15800198