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Title: The vasa gene as a marker for germ cell specification in the grasshopper Schistocerca gregaria
Author: Chang, C.-C.
Awarding Body: University of Cambridge
Current Institution: University of Cambridge
Date of Award: 2001
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The aim of this project is to understand how germ cells are specified in the grasshopper Schistocerca gregaria. I made expression constructs of the Schistocerca Vasa protein and the Drosophila Vasa protein, and produced them through bacteria hosts. Affinity purified Schistocerca and Drosophila vasa fusion proteins were sequentially injected into rabbits to induce antibodies cross reacting to conserved vasa-specific motifs. I affinity purified antibodies from two rabbits and named the antibodies Formosa 1 (for most vasa) and Formosa 2. Western blots demonstrate that both of the purified Formosa antibodies recognise protein specifically expressed in the Schistocerca ovary and testis. Both antibodies also recognise germ cells in the pea aphid. Formosa 2 antibody recognises Drosophila pole cells. Furthermore, like the anti-mouse vasa protein antibody, both Formosa 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 Schistocerca 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.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available