Investigation for Common Molecular Mechanisms by Comparison of EST from Purified Germ Cells

青竹胚胎是透明的，这使我们能够监测体内形态发生过程中发生的发育过程。我们利用胚系特异性表达基因VasA的调节区与绿色荧光基因融合开发了转基因青竹。利用这种转基因技术，我们可以观察生殖系的发育，这是未来卵子或精子的细胞谱系。我们已经建立了分离几个生殖细胞的技术，并建立了仅在种系中表达的EST的cDNA文库。我们最初的目的是将青海EST与小鼠种系EST进行比较，以揭示在物种之外普遍表达的基因。我们不能产生足够好的文库来代表青竹种系EST。然而，在我们测序的数千个EST中，发现了几个有趣的EST。通过EST的表达和功能分析，我们成功地追踪到了受精卵的种系。青竹生殖系是在原肠发育阶段检测到的，这表明生殖系的发育与哺乳动物的发育相似。我们的结果表明，生殖系的发育比其他脊椎动物更有可能，在其他脊椎动物中，生殖系可以通过特定的细胞结构来标记。此外，我们还证明了生殖系经历了三个发育阶段，有三种不同的向性腺区域迁移的方式。

medaka embryos are transparent, which allows us to monitor the development process occuring in morphogenesis in vivo. We have developed transgenic medaka using the regulatory regions of germline-specific expressed gene, vasa, fused with the green fluorescent gene. With this transgenics, we can observe the development of germline, the cell lineage for the future eggs or sperms. We have established the skills for isolating several germ cells and generated cDNA libraries for ESTs expressed exclusively in germline.Our initial purpose was to compare the medaka ESTs with mouse germline ESTs to reveal the genes commonly expressed beyond the species. We could not generate the libraries good enough for representing medaka germline ESTs. However, among the thousnads of ESTs we sequenced, several interesting ESTs have been found. By the expression and functional analyses of the ESTs, we successfully kept track of germline from fertilized eggs. Medaka germline is detected at the gastrulation stage, which has been suggesting that development of germline is similar to that seen in mammals. Our results indicate that germline development is more likely to that of other vertebrates where germline can be marked by specific cellular structures. Furthermore we demonstrated thatgermline goes through three steps of developmental process with three different modes of migration towards gonadal area.