Molecular Mechanisms of FOXL2, An Ovarian Failure Gene

描述（由申请人提供）：卵巢早衰影响高达1%的40岁女性。虽然卵巢早衰的病因在很大程度上仍不清楚，但已确定某些病例的遗传基础。编码叉头转录的基因中的突变，叉头L2（FOXL 2）与这种疾病相关。FOXL 2存在于卵巢中，初步数据显示，它定位于小型和中型卵泡的分化程度较低的颗粒细胞，并作为类固醇生成急性调节（星星）基因（颗粒细胞分化的标志物）的转录抑制因子发挥作用。由于FOXL 2可能作为颗粒细胞分化和类固醇生成的阻遏物发挥作用，我们建议评估FOXL 2对其他参与类固醇生成级联反应的基因的转录活性，这些基因含有推定的叉头一致位点。由于FOXL 2可能作为颗粒细胞分化的阻遏物，因此类固醇生成，我们将评估FOXL 2过表达后颗粒细胞中类固醇的产生。为了了解卵巢中FOXL 2调控的一些潜在机制，我们使用卵巢融合cDNA文库进行酵母双杂交筛选以分离FOXL 2相互作用蛋白。大肿瘤抑制基因1（LATS 1），一个假定的丝氨酸/苏氨酸激酶和卵巢肿瘤抑制基因，被鉴定为与FOXL 2强烈相互作用。LATS 1突变与FOXL 2突变一样，产生相似的卵巢表型，即卵巢早衰。因此，我们认为LATS 1和FOXL 2共享一个共同的卵泡调节途径。我们将首先在卵巢中定位LATS 1，然后定义LATS 1和FOXL 2之间的精确相互作用。由于LATS 1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，因此我们认为FOXL 2的转录活性将受磷酸化调控。因此，我们还将使用我们的功能测定以及通过细胞定位来确定LATS 1对FOXL 2的磷酸化及其对转录活性的调节。这项研究可以更好地了解卵巢早衰的机制。

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.