Fig. 4. Phenotypic classes identified from the RNAi screen.

(A) Protocol for RNAi screening in primary cultures. (B-F) Four distinct classes of muscle phenotype were distinguished based on the staining of Actin using phalloidin (left panels, and red in right panels), Mhc (middle panels) and of nuclei with DAPI (blue in right panels). (B) Wild-type control myotubes treated with dsRNAs targeting lacZ. (C) Class I (treated with mew dsRNAs). (D) Class II (treated with sls dsRNAs). (E) Class III (treated with Mlc2 dsRNAs). (F) Class IV (treated with Actin dsRNAs simultaneously targeting all Actin isoforms, including Act42A, Act57B, Act5C, Act79B, Act87E and Act88F). Note that the four phenotypic classes did not result from fewer fusions, as muscles contained the same number of nuclei as controls. Arrowheads point to the nuclei. Scale bar: 15 μm.