Lin H, Spradling A C
Department of Embryology, Carnegie Institution of Washington, Baltimore, MD 21210, USA.
Development. 1997 Jun;124(12):2463-76. doi: 10.1242/dev.124.12.2463.
Germline stem cells play a pivotal role in gametogenesis; yet little is known about how they are formed, how they divide to self-renew, and how these processes are genetically controlled. Here we describe the self-renewing asymmetric division of germline stem cells in the Drosophila ovarian germline, as marked by the spectrosome, a cytoplasmic structure rich in membrane skeletal proteins. The ontogeny of the spectrosome marks the lineage of germline stem cells. We identified two new groups of mutations in which the divisional asymmetry is disrupted. The first, which we refer to as ovarette (ovt) mutations, was shown to correspond to a novel class of mutations in the pumilio locus. Since pumilio is known to posttranscriptionally repress the expression of target genes at earlier stages of germ cell development, our results suggest that a similar activity is needed to maintain germ line stem cells. We have also identified a second and novel gene, piwi, whose mutations abolish germline stem cell division.
生殖系干细胞在配子发生过程中起着关键作用；然而，对于它们如何形成、如何分裂进行自我更新以及这些过程如何受到基因控制，我们却知之甚少。在此，我们描述了果蝇卵巢生殖系中生殖系干细胞的自我更新不对称分裂，其标志是性染色体体，这是一种富含膜骨架蛋白的细胞质结构。性染色体体的个体发育标志着生殖系干细胞的谱系。我们鉴定出了两组新的突变，其中细胞分裂不对称性受到破坏。第一组，我们称之为ovarette（ovt）突变，已证明它对应于pumilio基因座中的一类新突变。由于已知pumilio在生殖细胞发育的早期阶段会在转录后抑制靶基因的表达，我们的结果表明维持生殖系干细胞需要类似的活性。我们还鉴定出了第二个新基因piwi，其突变会消除生殖系干细胞的分裂。
