The Phenotype of <i>M⁻ Z⁻ tre1</i> Mutant Embryos

<div><p>Anterior is left in all figures.</p> <p>(A–F) Embryos are stained with anti-Vasa (brown) to mark germ cells. (A–D) Lateral views. (E–F) Top views. (A), (C), and (E) are wild-type embryos. (B), (D), and (F) are <i>tre1</i> mutant embryos. Wild-type germ cells migrate out of the PMG at stage 10 (A) and migrate toward mesoderm at stage 11 (C) and finally to the gonad at stage 13 (E), but in <i>tre1</i> mutant embryos, germ cells fail to leave the PMG ([B] shows stage 10 and [D] shows stage 11) and are mostly found “clumped” together in the middle of the gut at stage 13 (F).</p> <p>(G–J) High magnification view of wild-type (G and H) and <i>tre1</i> mutant (I and J) embryos stained with anti-Neurotactin (red) to mark cell membranes of midgut epithelium and germ cell-specific anti-Vasa (green). Wild-type germ cells are migrating out of the PMG at early stage 10 (G) and are outside of the PMG and thus at a different optical plane than PMG at late stage 10 (H). <i>tre1</i> germ cells, in contrast, do not migrate out of the PMG at stage 9/10 (I) and are still left inside the PMG and thus at the same optical level as the PMG cells at late stage 10 (J). Punctate appearance of anti-Vasa staining in <i>tre</i> mutant germ cells is likely due to heat fixation protocol used as it can also be observed in wild-type germ cells (data not shown).</p>