Friday, August 25, 2006


A wandering eye: Single cells come running to form an eye

Eyes are among the earliest recognisable structures in an embryo; they start off as bulges on the sides of tube-shaped tissue that will eventually become the brain. Researchers from the European Molecular Biology Laboratory (EMBL) in Heidelberg have now discovered that cells are programmed to make eyes early in development and individually migrate to the right place to do so. The study, published in this week's issue of the journal Science, overturns the textbook model of the process and suggests that also other organs might be formed by the movement of single cells rather than sheets of entire tissues.

Jochen Wittbrodt and his lab at EMBL made the discovery using advanced microscope techniques to track individual cells in the transparent embryos of a small fish called Medaka.

'You can think of the tube as a deflated balloon shaped like a Mickey Mouse,' Wittbrodt says. 'As the fish grows, the eyes gradually bulge out from the tube, the way Mickey Mouse ears expand as a balloon is filled with air. Most scientists have thought that cells in the neighbouring regions grow to make the bulges. What we've seen is that individual cells migrate to this area from the central region of the tube – as if to make ears, tiny rubber particles had to fly out from the air inside the balloon.'
The above is based on the Science report "Individual Cell Migration Serves as the Driving Force for Optic Vesicle Evagination" (Abstract)

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