Regulation of Vertebrate Gonad Formation by Fibroblast Growth Factor Signaling

 描述(申请人提供)：成纤维细胞生长因子(成纤维细胞生长因子)信号转导与上皮性卵巢癌的进展有关，许多成纤维细胞生长因子配体及其受体(FGFR)在发育中的脊椎动物性腺中表达。然而，成纤维细胞生长因子信号在正常性腺发育或功能中的作用仅在有限的背景下被确定。我们的长期目标是确定成纤维细胞生长因子信号在性腺发育、病理生理学以及生育中的作用，特别是在卵巢中。该应用的目的是确定成纤维细胞生长因子信号在早期性腺原基发育中所起的作用。我们的切入点是鉴定斑马鱼成纤维细胞生长因子配体编码基因的突变，该突变导致在体细胞性腺原基形成阶段生殖细胞迅速丧失。我们的中心假设是，成纤维细胞生长因子信号是早期体细胞性腺发育所必需的，我们的成纤维细胞生长因子突变体中的体细胞性腺缺陷继而导致生殖细胞的丧失。这一假设是基于申请人实验室的初步数据提出的。我们将通过以下三个具体目标来验证这一假说：1)表征成纤维细胞生长因子信号对性腺原基发育的空间需求；2)确定成纤维细胞生长因子信号在调控早期性腺发育中的作用；3)确定哪个成纤维细胞生长因子受体(S)是斑马鱼性腺发育所必需的。基于我们强大的初步数据，我们假设成纤维细胞生长因子配体是由早期性腺原基的体细胞产生的。在第一个目标下，我们将使用遗传马赛克分析来确定在哪些细胞中产生了成纤维细胞生长因子配体。在第二个目标中，我们将通过定义我们的成纤维细胞生长因子突变体的发育缺陷来确定成纤维细胞生长因子配体在性腺原基发育中所起的作用。我们将结合组织学、标记基因分析和转录图谱来验证我们的假设，即成纤维细胞生长因子信号促进和/或维持决定早期体细胞性腺命运的基因的表达。在我们的第三个目标下，我们将通过确定同源的成纤维细胞生长因子受体来确定哪些细胞对成纤维细胞生长因子配体有反应。这将使我们能够确定成纤维细胞生长因子信号调节性腺早期发育的机制。我们将利用成纤维细胞生长因子受体的功能丧失或必要时的条件突变来确定哪些是早期性腺发育所必需的。这项拟议的研究是创新的，因为它利用了一个独特的成纤维细胞生长因子突变体，使我们能够确定成纤维细胞生长因子信号在斑马鱼遗传适应性系统中早期性腺发育中的一个新角色。这项拟议的研究具有重要意义，因为它将定义一条调控早期性腺发育的分子途径，从而可能确定成纤维细胞生长因子信号缺陷如何解释其他健康女性中不明原因的不育症或卵巢早衰的原因，以及成纤维细胞生长因子信号在性腺起源癌症中的作用。

 DESCRIPTION (provided by applicant): Fibroblast growth factors (Fgf) signaling has been implicated in the progression of epithelial ovarian cancer, and numerous Fgf ligands and their receptors (Fgfr) are expressed in the developing and adult vertebrate gonads. However, the role of Fgf signaling in normal gonad development or function has only been defined in a limited context. Our long-term goal is to determine the roles Fgf signaling plays in gonad development, pathophysiology, and thus fertility, especially in the ovary. The objective of this application is o define the role Fgf signaling plays in the development of the early gonad primordium. Our entry point is the identification of a mutation in an Fgf ligand-encoding gene in zebrafish that results n rapid loss of germ cells during a stage when the somatic gonad primordium is forming. Our central hypothesis is that Fgf signaling is required for development of the early somatic gonad and that a somatic gonad defect in our Fgf mutant leads secondarily to loss of germ cells. This hypothesis has been formulated based on preliminary data from the applicant's laboratory. We will test this hypothesis by pursuing the following three Specific Aims: 1) Characterize the spatia requirement of Fgf signaling for development of the gonad primordium; 2) Determine the role of Fgf signaling in regulating the development of the early gonad; and 3) Determine which Fgf receptor(s) is required for development of the early zebrafish gonad. Based on our strong preliminary data, we hypothesize that the Fgf ligand is produced by the somatic cells of the early gonad primordium. Under the first aim we will determine in what cells the Fgf ligand is produced using genetic mosaic analysis. In the second aim, we will define what role the Fgf ligand plays in development of the gonad primordium by defining the developmental defect in our Fgf mutant. We will use a combination of histology, marker gene analysis and transcriptional profiling to test our hypothesis that Fgf signals promote and/or maintain the expression of genes that specify the early somatic gonad fate. Under our third aim we will define which cells respond to the Fgf ligand by determining the cognate Fgf receptor. This will allow us to define the mechanism by which Fgf signaling regulates early gonad development. We will use of loss-of-function, or when necessary, conditional mutations, in Fgf receptors to determine which are required for development of the early gonad. The proposed research is innovative because it utilizes a unique Fgf mutant that has enabled us to identify a novel role for Fgf signaling in early gonad development in the genetically amenable zebrafish system. The proposed research is significant because it will define a molecular pathway that regulates the development of the early gonad, and therefore is likely to identify how defects in Fgf signaling can account for cases of infertiliy or premature ovarian failure of unknown etiology in otherwise healthy women, and the role of Fgf signaling in gonad-originating cancers.