Picture from Benenati G et al. (2009) Mech Dev "Two cytochrome P450s in Caenorhabditis elegans are essential for the ...."

Fig. 2 cyp-31A2/A3(RNAi) embryos are permeable to dyes and fail to complete the extrusion of one of the polar bodies.Hoechst 33342 and FM 4-64 cannot penetrate the impermeable eggshell of a wild-type embryo (A). Note the staining of the 1st polar body (white arrowhead). The eggshell of cyp-31A2/A3(RNAi) embryos is permeable to these dyes: Hoechst 33342 stains DNA of the polar bodies and of the nuclei (white arrows), and FM 4-64 stains membranes and also some punctuate structures (B). In non treated embryos of the histone::GFP line, polar bodies are extruded at the anterior pole (C). In cyp-31A2/A3(RNAi)embryos, however, one of the polar bodies eventually fuses with the zygotic nucleus (D, empty arrowhead). cyp-31A3 is expressed in the gonads, oocytes and embryos (E, DIC image; F, GFP fluorescence).