The aim of this project is to understand how germ cells are specified in the grasshopper <I>Schistocerca gregaria</I>. I made expression constructs of the <I>Schistocerca </I>Vasa protein and the <I>Drosophila</I> Vasa protein, and produced them through bacteria hosts. Affinity purified <I>Schistocerca</I> and <I>Drosophila vasa </I>fusion proteins were sequentially injected into rabbits to induce antibodies cross reacting to conserved <I>vasa</I>-specific motifs. I affinity purified antibodies from two rabbits and named the antibodies <I>Formosa</I> 1 (for most vasa) and <I>Formosa</I> 2. Western blots demonstrate that both of the purified <I>Formosa</I> antibodies recognise protein specifically expressed in the <I>Schistocerca </I>ovary and testis. Both antibodies also recognise germ cells in the pea aphid. <I>Formosa </I>2 antibody recognises <I>Drosophila</I> pole cells. Furthermore, like the anti-mouse vasa protein antibody, both <I>Formosa </I>antibodies specifically detect a protein in the mouse testis. The size of the protein is very similar to that of the mouse Vasa protein. My immunostaining results show that putative germ cells lie in the outer germ band layer at a dorsal site in embryos from 15% to 30% of development. After 35% of development, they are guided into the bilateral gonadal mesoderm, which migrates dorsally toward the midline of the body. The bilateral gonad primordia coalesce around 70% of development. I conclude that the <I>Schistocerca</I> Vasa protein is a germ-cell marker. Using this marker I have traced the germline lineage through all developmental stages, though the identification of germ cells at early stages remains to be confirmed.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:597464 |
| Date | January 2001 |
| Creators | Chang, C.-C. |
| Publisher | University of Cambridge |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
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