Determining how Doublesex and sex-specific steroid hormone signaling control gonad development

项目摘要 在动物界，两性异形，或两性之间的表型差异，在大多数动物中都可以看到。 物种在果蝇中，控制两性异形的关键因素是Doubloxex（Dsx）， Doublemex/Mab-3相关转录因子（DMRT）家族。DMRT在以下方面发挥核心作用： 许多物种包括苍蝇、人类和小鼠的性别决定。尽管很少有Dsx目标 我们的实验室已经证明，Dsx调节性特异性类固醇激素蜕皮激素（E）信号传导 通过女性特异性蜕皮激素受体（EcR）表达，这有助于促进卵巢 在关键发育时间点抑制睾丸发育。生物信息学分析 已被用于预测Dsx靶点，其中许多是含有Broad-complex的转录因子， tramtrack和bric-a-brac（BTB）结构域，蛋白质-蛋白质相互作用基序。要识别扮演以下角色的Dsx目标， 在性腺的两性异形中的作用，我进行了BTB结构域蛋白的反向筛选， 推定的Dsx结合基序使用RNA干扰。结果，我发现，在体细胞中， 生殖腺导致严重的卵巢紊乱，在某些情况下，XX形成了退化的睾丸 动物鉴于这些发现，我假设mamo对正常发育至关重要。 果蝇卵巢，它的功能下游的Dsx和E信号，以帮助建立一个女性 性命运这一假设将通过首先检查Mamo的细胞类型特异性表达来解决。 在整个开发过程中，并使用dsx进行遗传相互作用测定。我将描述哪些细胞类型 使用细胞特异性标记物，确定mamo缺失是否会导致 卵巢的性别转换特性。第二个BTB结构域蛋白Chinmo已被证明是 在睾丸中的重要性，以及mamo和chinmo之间的关系，以及E信号如何调节这些 的因素，将被确定。这项工作将扩大目前关于DMRTs如何控制性行为的知识。 二型性，并可能揭示基因的关键性的性别身份在苍蝇和哺乳动物。由于 DMRTs在控制性别特异性发育方面的普遍性，了解其目标以及如何 功能对生殖健康非常重要，并有可能扩大我们对生殖健康的了解。 人类不育

PROJECT SUMMARY In the animal kingdom, sexual dimorphism, or phenotypic differences between the sexes, is seen in most species. In Drosophila, the key factor controlling sexual dimorphism is Doublesex (Dsx), the founding member of the conserved Doublesex/Mab-3 Related Transcription Factor (DMRT) family. DMRTs have central roles in sex determination across many species including flies, humans, and mice. Although few Dsx targets have been characterized, our lab has shown that Dsx regulates sex-specific steroid hormone Ecdysone (E) signaling through female-specific Ecdysone Receptor (EcR) expression, and that this functions to promote ovary development and repress testis development at a key developmental timepoint. Bioinformatic analyses has been used to predict Dsx targets, and many of these are transcription factors that contain a Broad-complex, tramtrack, and bric-a-brac (BTB) domain, a protein-protein interaction motif. To identify Dsx targets that play a role in sexual dimorphism of the gonad, I performed a reverse screen of BTB domain proteins containing putative Dsx binding motifs using RNA interference. As a result, I found that loss of mamo in somatic cells of the gonad led to severely disorganized ovaries and, in some cases, the formation of rudimentary testes in XX animals. Given these findings, I hypothesize that mamo is critical for proper development in the Drosophila ovary, and that it functions downstream of Dsx and E signaling to help establish a female sexual fate. This hypothesis will be addressed by first examining the cell-type-specific expression of Mamo throughout development and performing genetic interaction assays with dsx. I will characterize what cell types are affected in the absence of mamo using cell-specific markers and ascertain whether loss of mamo results in sex transformation properties of the ovary. A second BTB domain protein, Chinmo, has been shown to be important in the testis, and the relationship between mamo and chinmo, and how E signaling regulates these factors, will be determined. This work will expand current knowledge on how DMRTs control sexual dimorphism and could uncover genes critical for sexual identity in both flies and mammals. Due to the universal nature of DMRTs in controlling sex-specific development, understanding their targets and how they function is of great importance for reproductive health and has the potential to broaden our knowledge of human infertility.