Fig. 1: C. elegans possesses an SSNA-1 ortholog that plays a critical role in embryogenesis.

A Sequence alignment of various SSNA-1 orthologs. The amino acids are colored as follows: blue and red for negatively and positively charged residues, respectively, green for uncharged residues, and gold for hydrophobic residues. B Table showing percent identity (blue) and percent similarity (red) of SSNA-1 orthologs. C AlphaFold structural prediction of T07A9.13. D Embryonic viability of wild-type and ssna-1 mutant strains at 20 °C. Each datapoint represents progeny of a single hermaphrodite. Mean and SD are shown. n = 21 (WT), 12 (ssna-1(Δ)), 14 (ssna-1(Δ)/+), 14 (ssna-1^G7X), 21 (ssna-1^Δ2-17), 12 (ssna-1^Δ2-17/+), 21 (ssna-1^Δ2-18), 13 (ssna-1^Δ2-22), 14 (ssna-1^Δ100-105). E Embryonic viability of wild-type and ssna-1(Δ) strains at 25 °C. Each datapoint represents progeny of a single hermaphrodite. Mean and SD are shown. n = 14(WT), 14(ssna-1(Δ)). F Embryonic viability of wild-type and ssna-1(Δ) strains with or without the ssna-1 transgene (Tg). Note that when expressed in the wild type, the transgene does not affect viability, but when expressed in the ssna-1(Δ) mutant it fully rescues the embryonic lethal phenotype. Each datapoint represents progeny of a single hermaphrodite. Mean and SD are shown. n = 13 (WT Tg−), 13 (WT Tg+), 12 (ssna-1(Δ) Tg−), 13 (ssna-1(Δ) Tg+). G SSNA-1 is maternally required. Embryonic viability among the progeny of wild-type (magenta) or ssna-1(Δ) (blue) males and wild-type or ssna-1(Δ), fem-1(hc17) females. Note that embryonic lethality correlates with the genotype of the mother and not the father. No significant differences were observed in viability among the progeny sired by wild-type or mutant males. Each datapoint represents progeny of a single female. Mean and SD are shown. n = 18 (WT × WT), 17 (ssna-1(Δ) males × WT), 10 (WT × ssna-1(Δ) females), 9 (ssna-1(Δ) × ssna-1(Δ)). Source data are provided as a Source Data file.