Bhat K M
Department of Cell Biology, Emory University School of Medicine, Atlanta, Georgia 30322, USA.
Genetics. 1999 Apr;151(4):1479-92. doi: 10.1093/genetics/151.4.1479.
In a variety of tissues in eukaryotes, multipotential stem cells are responsible for maintaining a germinal population and generating a differentiated progeny. The Drosophila germline is one such tissue where a continuous supply of eggs or sperm relies on the normal functioning of stem cells. Recent studies have implicated a possible role for the posterior determinant gene nanos (nos) in stem cells. Here, I report that nanos is required in the Drosophila female germline as well as in the male germline. In the female, nos is required for the functioning of stem cells. In nos mutants, while the stem cells are specified, these cells divide only a few times at the most and then degenerate. The loss of germline stem cells in nos mutant mothers appears to be due to a progressive degeneration of the plasma membrane. Furthermore, following germ cell loss, the germaria in the nos mutant mothers appear to carry on massive mitochondrial biogenesis activity. Thus, the syncytia of such germaria are filled with mitochondria. In the male germline, the male fertility assay indicates that nos appears to be also required for the maintenance of stem cells. In these mutant males, spermatogenesis is progressively affected and these males eventually become sterile. These results indicate novel requirements for nos in the Drosophila germline.
在真核生物的多种组织中，多能干细胞负责维持一个生发群体并产生分化的后代。果蝇生殖系就是这样一种组织，卵子或精子的持续供应依赖于干细胞的正常功能。最近的研究表明，后部决定基因纳米（nos）在干细胞中可能发挥作用。在此，我报告纳米在果蝇雌性生殖系以及雄性生殖系中都是必需的。在雌性中，纳米是干细胞发挥功能所必需的。在纳米突变体中，虽然干细胞已确定，但这些细胞最多只分裂几次，然后就会退化。纳米突变体母亲中生殖系干细胞的丧失似乎是由于质膜的逐渐退化。此外，在生殖细胞丧失后，纳米突变体母亲中的卵巢管似乎进行大量的线粒体生物合成活动。因此，这种卵巢管的合胞体充满了线粒体。在雄性生殖系中，雄性生育力测定表明纳米似乎也是维持干细胞所必需的。在这些突变体雄性中，精子发生逐渐受到影响，这些雄性最终变得不育。这些结果表明纳米在果蝇生殖系中有新的需求。
