Molecular Mechanisms of FOXL2, An Ovarian Failure Gene

描述(申请人提供)：卵巢早衰影响高达1%的妇女到40岁。虽然卵巢早衰的病因在很大程度上仍不清楚，但已确定了部分病例的遗传学基础。编码叉头转录的基因突变，叉头L2(FOXL2)与这种疾病有关。FOXL2存在于卵巢中，初步研究表明，FOXL2定位于中、小卵泡中分化较差的颗粒细胞，是颗粒细胞分化的标志--类固醇合成急性调节基因(STAR)的转录抑制因子。由于FOXL2可能作为颗粒细胞分化和类固醇合成的抑制因子，我们建议评估FOXL2在其他涉及类固醇发生级联的基因上的转录活性，这些基因包含假定的叉头共识位点。由于FOXL2可能作为颗粒细胞分化的抑制因子，从而抑制类固醇的生成，我们将评估FOXL2过表达后颗粒细胞中类固醇的产生。为了了解FOXL2在卵巢中调控的一些潜在机制，我们使用卵巢融合cDNA文库进行了酵母双杂交筛选，以分离FOXL2相互作用的蛋白。大肿瘤抑制基因1(LATS1)是一种可能的丝氨酸/苏氨酸激酶和卵巢肿瘤抑制基因，与FOXL2有很强的相互作用。LATS1的突变，就像FOXL2的突变一样，会产生类似的卵巢表型，即卵巢早衰。因此，我们认为LATS1和FOXL2具有共同的卵泡调节途径。我们将首先在卵巢中定位LATS1，然后定义LATS1和FOXL2之间的精确相互作用。由于LATS1是一种丝氨酸/苏氨酸激酶，而其他叉头家族成员受磷酸化调控，我们认为FOXL2的转录活性将通过磷酸化来调节。因此，我们还将使用我们的功能分析以及通过细胞定位来确定LATS1对FOXL2的磷酸化及其对转录活性的调节。这项拟议的研究可能会更好地理解卵巢早衰的机制。

DESCRIPTION (provided by applicant): Premature ovarian failure affects up to 1% of women by the age of 40. Although the etiology of premature ovarian failure remains largely unknown, a genetic basis has been determined for selective cases. Mutations in the gene encoding a forkhead transcription, Forkhead L2 (FOXL2) has been associated with this disorder. FOXL2 is present in the ovary and preliminary data reveals that it is localized to less differentiated granulosa cells of small and medium follicles and functions as a transcriptional represser of the Steroidogenic Acute Regulatory (StAR) gene, a marker of granulosa cell differentiation. Since FOXL2 may function as a represser of granulosa cell differentiation and steroidogenesis, we propose to evaluate FOXL2 transcriptional activity on other genes involved in the Steroidogenic cascade which contain putative forkhead consensus sites. Since FOXL2 may function as a represser of granulosa cell differentiation and hence steroidogenesis, we will evaluate steroid production in the granulosa cell following FOXL2 overexpression. In order to understand some of the underlying mechanism of FOXL2 regulation in the ovary, we performed a yeast two-hybrid screen using an ovarian fusion cDNA library to isolate FOXL2-interacting proteins. Large Tumor Suppressor Gene 1 (LATS1), a putative serine/threonine kinase and ovarian tumor suppressor gene, was identified to interact strongly with FOXL2. Mutations in LATS1, like mutations in FOXL2 produce a similar ovarian phenotype, premature ovarian failure. Thus, we propose that LATS1 and FOXL2 share a common pathway for follicular regulation. We will first localize LATS1 in the ovary, followed by defining the precise interaction between LATS1 and FOXL2. Since LATS1 is a serine/threonine kinase, and other forkhead family members are regulated by phosphorylation, we propose that FOXL2 transcriptional activity will be regulated by phosphorylation. Thus, we will also determine phosphorylation of FOXL2 by LATS1 and its regulation of transcriptional activity using our functional assay as well as through cellular localization. The proposed study could provide a better understanding of the mechanisms underlying premature ovarian failure.