Fig. 5: SSNA-1 functions during centriole assembly.

A Embryonic viability of progeny from wild type, zyg-1(it25), ssna-1(Δ), and zyg-1(i25); ssna-1(Δ) strains at 22.5 °C. Each data point represents the progeny of a single hermaphrodite. Mean and SD are shown. n = 10 (WT), 10 (zyg-1(it25)), 10 (ssna-1(Δ)), 10 (zyg-1(it25); ssna-1(Δ)). ***p = 0.0003, ****p < 0.0001 as determined with a one-way ANOVA with Tukey’s multiple comparisons test. B Single frames taken from time-lapse recordings of the indicated strains expressing GFP::histone and SPD-2::mCherry. Each image shows a two-cell stage embryo. A few zyg-1(it25) embryos exhibit monopolar spindles (magenta arrowhead), while ssna-1(Δ) embryos only possess bipolar spindles (white arrowheads). The zyg-1(it25); ssna-1(Δ) double mutant embryos exhibit a mixed phenotype, with monopolar spindles (magenta arrowheads) or tripolar spindles (cyan arrowheads). C Quantification of spindle defects observed through the first two cell divisions at 22.5 °C. The zyg-1(it25); ssna-1(Δ) double mutant embryos display twice as many monopolar spindles as zyg-1(it25) embryos. The double mutant also assembles multipolar spindles which are not observed in either single mutant. D Co-sedimentation assay showing SSNA-1 and ZYG-1 interact. Proteins were incubated alone (left) or in various combinations (right), separated into soluble (S) and pellet (P) fractions by centrifugation, and then detected by immunoblotting. Note that ZYG-1 is found in the soluble fraction when incubated alone or with microtubules but shifts to the pellet fraction upon incubation with SSNA-1. E Quantitation from three-independent co-sedimentation experiments. Mean and SD are shown. Source data are provided as a Source Data file.