Extended Data Fig. 9: Genetics in C. elegans support roles of SYF2.

a. Ce SYF2 and Ce SDE2 bind the U2-U6 helix II in the ILS″. U2 snRNA, U6 snRNA, SYF2 and SDE2 are shown as ribbons and DHX15 is shown as an outline. b. An AlphaFold2 Multimer prediction of human SDE2 with SYF2 and SYF1 suggests an identical binding mode of Hs SDE2, however it was not observed in the experimental density due to limited local resolution. c. Sequence alignments of Ce and Hs SDE2 and SYF2. d. Schematic of syf-2 mutant alleles generated by CRISPR-Cas9 in C. elegans. e. Viability of syf-2 mutant animals. Single worms of the indicated genotypes were placed on individual plates at the L3/L4 stage and grown at 20 °C for 96 h. Animals with deletion of helix 1 (Δanchor) are viable as homozygotes, but animals with deletion of helices 1 and 2 (Δanchor+wedge) are only viable as heterozygotes; homozygous mutants are thus progeny of heterozygous mothers. Sterility was scored as the inability to produce numerous progeny that developed into L4 larvae. A few sterile animals still produced <10 embryos or early larvae but these did not develop further. f. Viability of wild-type or syf-2 Δanchor mutant strains treated with empty vector (e.v.) or anti-syf-2 RNAi, at standard (20 °C) or low (15 °C) culture temperatures. Worms were synchronized as L1 larvae, placed on RNAi plates and grown at the corresponding temperatures. Viability was assessed as the total number of F1 progeny that reached the L4 stage. N = 3 animals were analyzed for assays at 15 °C and N = 5 animals were analyzed for assyays at 20 °C. P-values from pairwise two-sided t-tests are indicated. g. Measurement of the synthetic effect of RNAi against sde-2 on syf-2 Δanchor mutant viability. Viability was measured as described in e at both 15 °C and 20 °C. RNAi against mog-7/PAXBP1 was used as a positive control as an essential splicing protein. N = 3 animals were analyzed for assays at 15 °C and N = 5 animals were analyzed for assyays at 20 °C. P-values from pairwise two-sided t-tests are indicated.