Fig. 1
Coiling is a motor impairment of C. elegans that correlates with α-synuclein protein levels. (a) Top: Circularity values per frame from recordings of individual non-transgenic C. elegans (N2 wild-type strain) or transgenic C. elegans expressing A30P α-synuclein in dopaminergic neurons (syn). Bottom: Processed images (numbered 1 to 4) of the animal corresponding to different circularity values. Normal sinusoidal body shape corresponded to circularity values of ~ 0.2 (left, image 2). Body shape during an omega turn corresponded to circularity values of ~ 0.5 (left, images 1 and 3; right, image 4). Coiling animals had circularity values ranging from ~ 0.6 to almost 1 (left, image 4; right, images 1 and 2). (b) Percentage of frames with a circularity value > 0.6 for individual N2 (N = 40 animals), syn (N = 40 animals), or animals that do not express α-synuclein but have the same genetic background (tzIs3) as syn animals (No syn) (N = 41 animals) (one-way ANOVA with Tukey’s post-hoc test, ***p < 0.001). Each data point represents an individual animal. (c) Recordings were performed of N2, syn, or control animals expressing GFP instead of α-synuclein in dopaminergic neurons (N > 10 populations of n = 10 animals per strain), and circularity values were calculated for each animal in each frame. Range of circularity values was divided into bins of 0.05 (20 bins from 0 to 1.0). Number of circularity values within each bin were counted and percentage relative to all counts was calculated (presented as log10 of percentage). Circularity value of 0.6 (dotted line) was selected as the threshold to isolate the coiler phenotype. (d) Coiler scores of syn animals (N = 3 populations of n = 10 animals) and known coiler mutant strains: unc-10(e102) (N = 9 populations of n = 10 animals), unc-69(e587) (N = 9 populations of n = 10 animals), and unc-17(e245) (N = 9 populations of n = 10 animals), normalized to control GFP animals (one-way ANOVA with Tukey’s post-hoc test, **p < 0.01, ****p < 0.0001 relative to syn animals). Each data point represents an individual population. (e) Coiler scores of animals expressing wild-type (WT), mutant A30P, or mutant A53T α-synuclein in dopaminergic neurons. Control C. elegans express GFP only in dopaminergic neurons (GFP) or do not express either α-synuclein or GFP (No syn). Coiler scores are normalized to control GFP animals (N = 10 populations of n = 10 animals for each strain; each data point represents an individual population) (one-way ANOVA with Tukey’s post-hoc test, ****p < 0.0001 relative to GFP). (f) Correlation of coiler score and α-synuclein protein levels for 12 different C. elegans strains expressing α-synuclein in dopaminergic neurons (Pearson correlation, r = 0.58, p < 0.05). Each point of the scatter plot represents one animal strain. The syn protein:total protein ratio for the 3 lowest expressing strains ranged from 0.03 to 0.2 × 10− 6