Fig. 3. Defective prospero mRNA localization in the deletion mutant. (A,B,E,F) Ventral views of embryos at low magnification. (C,D) Sagittal views of embryos at medium magnification. (G-J) Sagittal views of embryos at high magnification. (A,B) RNA in situ hybridization for miranda mRNA expression shows normal miranda mRNA expression and subcellular localization in wild-type and osp29 mutant embryos (arrows indicate cells with RNA localization). (C,D) The Miranda protein is detectable, although less abundant and in fewer cells, in the deletion mutant (arrows indicate cells with subcellular localization). (E,F) The expression of prospero mRNA is detectable in the neuroblasts of mutant embryos albeit slightly lower in early stage; the intense midline (ML) staining in the mutant is probably due to expansion of midline cell fate in the absence of Snail in the blastoderm. Older mutant embryos (H) accumulate higher levels of prospero RNA, similar to that of wild type (G). The apparently lower level in the mutant in earlier stages may also be due to the loss of subcellular localization (compare G with H, arrows indicate localization). This localization defect can be rescued (arrows) in the presence of P[wor, esg] transgenes (I). In inscuteable mutant embryos (J), the Prospero protein expression is clearly seen in some GMCs (arrowhead) and neuroblast (arrow) nuclei. This phenotype is different from Prospero protein pattern in osp29 embryos (compare with Fig. 4B).