Fig. 1

Isolation of a C. elegans loss-of-function sams-1 mutant exhibiting enlarged embryonic “bubbles.” a DIC images of embryos from wild-type (WT) worms and the sams-1(t3210) mutant, isolated by EMS mutagenesis. Enlarged lipid droplets in a sams-1(t3210) embryo are indicated by arrows. b Structure of SAMS-1. The 3 functional domains of SAMS-1 are indicated with blue boxes. The numbers represent amino acid residues in SAMS-1. The A105V substitution observed in the sams-1(t3210) mutant is depicted. Multiple sequence alignments of SAMS-1 are shown. c In silico analysis using web-based tools to predict the impact of the A105V substitution on the structure and function of SAMS-1. The predictions are based on single asterisks the physiochemical properties of the exchanged amino acids; double asterisks the probability of impairment of structural and functional protein features; and triple asterisks evolutionary conservation. d Model of the SAMS-1 crystal structure predicted by HOPE. The A105V substitution site is shown in magenta. e Survival rates (% survival) of adult wild-type, sams-1 mutant, and sams-1 RNAi-treated worms. Worms fed a gcs-1 RNAi construct were used as positive controls. L4440, RNAi empty vector. Larvae were cultured on 4 mM sodium arsenite NGM plates for 24 h. Three independent experiments, each comprising 30 worms per strain, were performed. Significant differences compared to wild-type worms are indicated by asterisks and were calculated in unpaired t tests (**p < 0.01; ***p < 0.001) (color figure online)