Fig. 5. (A) spn-4 embryos fail to produce intestinal and pharyngeal muscle cells, but make extra body wall muscle and germline. Fluorescence micrographs of terminally differentiated wild-type (left column) and spn-4 mutant embryos (right column). Intestinal cells were detected with the monoclonal antibody (mAb) J126; pharyngeal muscle cells with the mAb 3NB12; germline cells with polyclonal antibodies that recognize the P-granule component PGL-1; body wall muscle cells with a myo-3::GFP transgenic line. Micrographs of germline and body wall muscle cells in spn-4 embryos were obtained using confocal microscopy, the remaining micrographs were obtained using epifluorescence. See the text for numbers of embryos examined. (B) spn-4 is required for specifying pharyngeal muscle in par-3, mom-2 and pie-1 mutants. In par-3(it71) and par-3(it71);spn-4(or191ts) embryos, pharyngeal muscle cells were detected with the mAb 3NB12; in mom-2 and pie-1 RNAi mutant embryos pharyngeal muscle cells were detected using the GFP reporter ceh-22::GFP. In each case, only background staining is detected in the double mutant embryos. All micrographs obtained using epifluorescence microscopy. See the text for numbers of embryos examined.