Wrapping it Up

Just as electrical wires are surrounded by plastic insulation that allows electricity to flow smoothly and avoids short circuits, the nerves in your brain are wrapped in biological insulation known as myelin, produced by specialised cells called oligodendrocytes (highlighted green in this image of the cells in the brain of a zebrafish embryo). Curiously, the same oligodendrocyte can make different sized myelin sheaths, although it’s not known exactly how this is controlled. Myelin sheaths contain hundreds of molecular messages known as mRNA (highlighted pink), which provide instructions for making proteins – the building blocks of cells. Researchers have now discovered that these mRNAs contain a specific ‘homing signal’ that directs them to go into myelin sheaths and promote new growth. Although these experiments have been done using zebrafish, similar mechanisms are likely to be at work in our own brains, shedding light on how our nervous system is built during development.

Written by Kat Arney

Kat Arney

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Dr Kat Arney is an award-winning science writer, broadcaster and public speaker, and is the founder and Creative Director of First Create The Media.

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• Image from work by Katie M. Yergert and colleagues
• Department of Pediatrics, University of Colorado Anschutz Medical Campus, Aurora, CO, USA
• Image originally published with a Creative Commons Attribution 4.0 International (CC BY 4.0)
• Published in PLOS Biology, January 2021