Fig. 1. Loss-of-function mutations in isw-1 suppress the synMuv phenotype of lin-53; lin-15A mutants. (A) Bright-field micrographs of C. elegans 24 hours after the fourth larval stage. Vulvae and psuedovulvae are marked with white triangles and black triangles, respectively. (Top) The wild-type strain has no pseudovulvae. (Middle) The synMuv mutant lin-53(n833); lin-15A(n767) has three pseudovulvae. (Bottom) The lin-53(n833); isw-1(n3294); lin-15A(n767) triple mutant has no pseudovulvae. Bacteria, embryos or bubbles were removed from the images. Scale bar: 100 µm. (B) The genomic structure of isw-1. Exons are indicated by black boxes; 5' and 3' untranslated regions are indicated by white boxes. Predicted translation initiation and termination codons and the polyadenylation site are shown. The locations of the missense mutations and deletion allele are indicated. (C) A representation of the domain structure of the ISW-1 protein. ISW-1 is similar to Drosophila ISWI and other family members, especially in the named domains (see text). The amino acid substitutions of the two missense alleles and the locations of these mutations and the deletion allele are indicated. An alignment of ISW-1 with S. cerevisiae SWI2/SNF2 and Drosophila ISWI is in Fig. S1.