Getting from A to B

Rebrafish retinal cells, optic nerves, and glia are labeled. Retinal cells send projections through the optic nerve to their targets in the brain.Dr Kara Cerveny & Dr Steve Wilson Wellcome Images
Visual System of 4 day old zebrafish
Dr Kara Cerveny & Dr Steve Wilson Wellcome Images

How do individual cells find their way in the complex environment of a human body or a small worm? Some cells need to navigate from where they are born to where they are needed (like immune cells). Other cells need to send out a very long extension to make a contact with a very specific target (like a neuron sending an axon through layers and layers of other neurons to reach its connection in a circuit). I used to study a very specific example (one motor neuron connecting to one specific muscle) of this type of navigation in the fruit fly. Continue reading “Getting from A to B”