Evaluating Motor Impairment in C. elegans Models Using the Radial Locomotion Assay

Abstract

Source: Currey, H. N., et al. Evaluation of Motor Impairment in C. elegans Models of Amyotrophic Lateral Sclerosis. J. Vis. Exp. (2021).

This video demonstrates the use of a radial locomotion assay to evaluate motor dysfunction in C. elegans expressing either wild-type or ALS-mutant human TDP-43 protein. Worms with varying levels of wild-type or mutant TDP-43 expression are allowed to crawl, and their movement is measured by the radial distance traveled from the central point on the assay plate. The assay distinguishes between mild, moderate, and severe motor impairments based on the distance traveled by the different C. elegans strains.

Protocol

1. Radial locomotion assay

1. Prepare 100 mm or 150 mm diameter Petri dishes about half full of nematode growth media (NGM) and seeded with a uniform lawn of OP50 bacteria to cover the entire surface of the agar.
2. Flip the NGM assay plates upside-down and label the bottom with an identifier for the C. elegans strains to be assayed, 2 plates per strain (Figure 1A).
3. Make a small dot with the marker in the center of the upside-down plate (Figure 1A).
4. While working with a dissecting microscope, transfer 15-20 staged matched worms to the center of the assay plate directly over....

Results

Figure 1: Radial locomotion assay workflow. Panels A-E show the generalized steps of the radial locomotion assay. The steps are as follows: (A) NGM Plates, with OP50 seeded to the edges, are prepared by labeling an.......

Materials

List of materials used in this article

Name	Company	Catalog Number	Comments
C. elegans	Caenorhabditis Genetics Center (CGC)	-	Aquire your strains as desired, N2 is a useful control strain
Disposable pasteur pipets, borosilicate glass	VWR	14673-010	Glass pipet used to create worm pick - hold glass pipette in one hand and ~1" of platinum wire (held by pliers) in the other over a flame to join.
Disposable petri dishes, 35x10mm	VWR	10799-192	Assay plates for WormLab Imaging System
Disposable petri dishes, 60x15mm	VWR	25384-090	Stock plates for worms
Disposable petri dishes, 100x15mm	VWR	25384-302	Standard radial locomotion assay plate
Disposable petri dishes, 150x15mm	VWR	25384-326	Longer time frame radial locomotion assay plate
Dissecting microscope	Leica	M80	Scope for maintaining worms and setting up radial locomotion assays
Fine-tipped markers	VWR	52877-810	Need at least 2 colors for radial locomotion assays. Fine tips required for accuracy.
Flatbed Scanner	Amazon	Epson Perfection V850	Optional for radial locomotion assay. Protocol assumes a resolution of 300dpi, most scanners would work fine
NGM (Nematode Growth Medium)	VWR	76347-412	Medium used to cultivate C. elegans. Can be made from scratch, see WormBook: Maintenance of C. elegans
OP50 bacteria	Caenorhabditis Genetics Center (CGC)	OP50	Primary food source for C. elegans
p1000 pipettor	VWR	76207-552	Pipettor, used in swimming assay
p1000 tips	VWR	83007-384	Tips for pipettor, used in swimming assay
Platinum wire, 0.2032mm diameter	VWR	BT136585-5M	Fine gauge platinum wire used to create worm pick - hold glass pipette in one hand and ~1" of platinum wire (held by pliers) in the other over a flame to join.
Ruler	VWR	56510-001	Need to score radial locomotion assays
ImageJ	NIH	-	Optional free software provided by the NIH - https://imagej.nih.gov/ij/
WormLab Imaging System	MBF Bioscience	WormLab	The Imaging System includes WormLab hardware (bright field stage, camera, and housing) and WormLab software. https:// www.mbfbioscience.com/wormlabimaging- system