(A) Alignment of mature miR-1 sequences indicates deep conservation. The seed sequence of each miR-1 family member is highlighted in blue and the conservation of C. elegans mir-1 is highlighted in gray. hsa = Homo sapiens, mmu = Mus musculus, gga = Gallus gallus, xtr = Xenopus tropicalis, dre = Danio rerio, dme = Drosophila melanogaster, cel = Caenorhabditis elegans. (B–C) Visualization of Q40::YFP aggregates (green foci) in (B) wild-type and (C) mir-1(gk276) animals. Scale bar, 50 μm. (D) Quantification of Q40::YFP aggregation in wild-type, mir-1(gk276), mir-1(n4102) and mir-80(nDf53) animals. (E) Quantification of Q40::YFP aggregates in wild-type, mir-1(gk276) and mir-1(gk276) animals transgenically-expressing the mir-1 hairpin in body wall muscle (myo-3 promoter), pharynx (myo-2 promoter) or intestine (ges-1 promoter). Mutation of the mir-1 seed sequence (Muscle mir-1*) abrogates rescue from body wall muscle. Mature mir-1 sequences (wild-type mir-1 or mutated mir-1*) used for rescue experiments are shown (box). Red nucleotides indicate the mutations in the seed sequence used in mir-1* rescue experiments, which are predicted to hinder interactions with mir-1 targets. (F) Body bends in wild-type, mir-1(gk276) and mir-1(n4102) mutant animals expressing α-synuclein::YFP. (G) Survival of wild-type, mir-1(gk276) and mir-1(n4102) animals after exposure to 4 hr of 35°C heat stress. Transgenic expression of wild-type mir-1 hairpin, but not mutated mir-1*, in body wall muscle rescues mir-1(gk276) heat stress sensitivity. All experiments were performed in triplicate and at least 10 animals were scored per experiment. Error bars show standard error of the mean (SEM). ****p<0.0001, n.s. not significant to the control (one-way ANOVA analysis, followed by Dunnett’s multiple comparison test).