Abstract
The optical transparency of the nematode Caenorhabditis elegans makes it possible to monitor the behaviour of fluorescently labelled proteins in a living multicellular organism. This study investigates the suitability of mNeonGreen as a fluorescent tag for studying proteins of interest in the nervous system of adult C. elegans . Despite its reported brightness, stability, and monomeric nature, our findings reveal that mNeonGreen forms solid aggregates in C. elegans neurons, particularly upon plasmid overexpression. We anticipate that this property may lead to artefacts when analysing for example the subcellular distribution or turnover of a tagged protein of interest.