Keisman E L, Baker B S
Department of Biological Sciences, Stanford University, Stanford, CA 94305, USA.
Development. 2001 May;128(9):1643-56. doi: 10.1242/dev.128.9.1643.
The integration of multiple developmental cues is crucial to the combinatorial strategies for cell specification that underlie metazoan development. In the Drosophila genital imaginal disc, which gives rise to the sexually dimorphic genitalia and analia, sexual identity must be integrated with positional cues, in order to direct the appropriate sexually dimorphic developmental program. Sex determination in Drosophila is controlled by a hierarchy of regulatory genes. The last known gene in the somatic branch of this hierarchy is the transcription factor doublesex (dsx); however, targets of the hierarchy that play a role in sexually dimorphic development have remained elusive. We show that the gene dachshund (dac) is differentially expressed in the male and female genital discs, and plays sex-specific roles in the development of the genitalia. Furthermore, the sex determination hierarchy mediates this sex-specific deployment of dac by modulating the regulation of dac by the pattern formation genes wingless (wg) and decapentaplegic (dpp). We find that the sex determination pathway acts cell-autonomously to determine whether dac is activated by wg signaling, as in females, or by dpp signaling, as in males.
多种发育线索的整合对于后生动物发育基础的细胞特化组合策略至关重要。在果蝇生殖器成虫盘（其发育形成两性异形的生殖器和肛门附属器）中，性别身份必须与位置线索整合，以便指导适当的两性异形发育程序。果蝇的性别决定由一系列调控基因控制。该系列中已知的位于体细胞分支的最后一个基因是转录因子双性基因（doublesex，dsx）；然而，在两性异形发育中起作用的该系列的靶标仍然难以捉摸。我们发现，腊肠犬基因（dachshund，dac）在雄性和雌性生殖器盘中差异表达，并在生殖器发育中发挥性别特异性作用。此外，性别决定系列通过调节模式形成基因无翅基因（wingless，wg）和果蝇转化生长因子β基因（decapentaplegic，dpp）对dac的调控，介导了dac的这种性别特异性表达。我们发现，性别决定途径以细胞自主方式起作用，以确定dac是如在雌性中那样由wg信号激活，还是如在雄性中那样由dpp信号激活。
