Axon Ax-off

Like trees growing in the wild, the branches or axons of our nerve cells reach out as they develop. In the optic tract of a zebrafish, some branches of these retinal ganglion cells are ‘pruned’ to guide the accurate shape of circuits behind its eyes. Like snipping at a bonsai tree (although about 1000 times smaller), cells on one side of the tract (highlighted in red) send signals that help to cut off stray axons of cells on the other side (blue), leaving grouped or 'sorted' neurons behind (seen on the right). Researchers using CRISPR/Cas9 technology block the activity of ones of the genes involved, gpc3, leaving the optic tract in a disorganised unpruned state (left and middle). Insight into this molecular tree surgery might influence therapies for the human brain, which also uses a form of gpc3 – offering a helping hand in shaping neural circuits that develop errant branches.

Written by John Ankers

John Ankers

Writer

A former researcher in systems biology, John is now an online biology tutor and professional coach supporting the wellbeing of scientists and NHS professionals. He's writing, too, of course.

Website

• Image from work by Olivia Spead, Trevor Moreland and Cory J. Weaver, and colleagues
• Department of Biological Sciences, University of South Carolina, Columbia, SC, USA
• Image originally published with a Creative Commons Attribution 4.0 International (CC BY 4.0)
• Published in Cell Reports, February 2023