Fig. 3. Loss of isw-1 function suppresses multiple cell-fate defects caused by mutations in class B synMuv genes. (A) isw-1(n3294) suppresses the ectopic expression of PGL-1 in the soma of L1 larvae in the class B synMuv mutant lin-15B(n744). Anti-PGL-1 staining is shown in green and nuclei (4,6-diamidino-2-phenylindole (DAPI) staining) are shown in blue. Scale bars: 10 µm. (B) Loss of isw-1 function suppresses the Tam phenotype of lin-15B animals and represses normal transgene expression. The ccIs4251 reporter is a simple repetitive transgene that expresses GFP in the nuclei of body-wall muscles. From left to right, ccIs4251 was expressed in the following backgrounds: wild type, isw-1(RNAi), lin-15B(n744) and isw-1(RNAi); lin-15B(n744). Scale bars:100 µm. A quantification of the Tam experiments is found in Fig. S4. (C) isw-1 is required for the RNAi sensitivity of the class B synMuv mutant lin-15B(n744). After exposure of animals to cel-1 RNAi, the number of arrested L2 larvae was scored in at least three independent experiments. The average percent of L2 arrested larvae is shown. Error bars indicate standard deviations. (D) The activity of isw-1 and nurf-1 are required for the larval-lethal phenotypes of mep-1(q660) and let-418(n3536) mutants. The percent of sterile adults present at 25°C reflects the suppression of larval lethality. Error bars indicate standard deviations.