Figure 1. A human Timothy syndrome mutation in the C. elegans voltage-gated calcium channel ortholog
egl-19 by CRISPR-Cas9 HR causes a developmental arrest phenotype. a. A schematic of the human TS type 1 gain-of-function missense mutation (G406R) in the C. elegans ortholog EGL-19 (G369R). b. CRISPR-Cas9 HR mix was injected into 55 young adult C. elegans. Of 210 F1 roller progeny, 3 were heterozygous for the desired point mutation detected by a PCR/XbaI screen. c. Sequence alignment result from a HR positive heterozygous adult animal with the TS mutation. PAM sequence is underlined and small-guide RNA is beneath the arrow. Raw sequence trace result below shows the heterozygous TS A/G peak at the point mutation site (red arrow). d. C. elegans developmental arrest phenotype harboring the homozygous TS type 1 human mutation. e. Proposed model illustrating possible mechanisms underlying the unexpected C. elegans phenotype caused by the human TS type 1 mutation, which may result from worm-specific dysfunction in
egl-19 expression, trafficking, or protein function.