“Roundabouts mediate Slit axon and glial cell guidance at the midline of the zebrafish forebrain.”

Michael J.F. Barresi, Ph.D., Smith College, Northampton, MA 01063

Wiring of the nervous system utilizes an elaborate communication system between pathfinding axons and their growth environment. Many different cellular and molecular guidance cues influences an equally diverse array of cell receptors. How do all of these cues simultaneously function to point axons in the right direction? To answer this question we have characterized a simple system in the zebrafish forebrain to simultaneously assay commissural axons, their astroglial growth substrate, and the Slit-Robo guidance system. We show that commissural axons grow along a bridge-like structure made of astroglial cells. In addition, Slit functions not only to guide axons across the forebrain, but also to set up the correct positioning of the midline astroglial bridge. Interestingly, roundabouts (robo), the Slit receptors, are differentially expressed in commissural neurons and in the astroglial bridge. We propose to fully exploit the embryological, molecular and genetic techniques available to zebrafish to breakdown the synergistic roles of the Slit-Robo guidance system during astroglial bridge assembly and commissure formation in the diencephalon.

Michael J.F. Barresi, Ph.D.
Assistant Professor of Biology
Smith College
44 College Lane
Northampton, MA 01063

Phone: 413-585-3697
Fax: 413-585-3786

mbarresi@email.smith.edu