Fragile X pre-mutation and ovarian insufficiency

描述（由申请人提供）：该项目直接响应NIH的号召，开发和表征专门适合研究FMR 1前突变对卵巢功能不全影响的模型。脆性X智力低下1基因（FMR 1）含有一系列位于5'UTR的约30个CGG三联体重复。CGG重复序列的数目突变扩增至大于200个三联体导致脆性X综合征。目前研究的重点是CGG重复序列的前突变扩展到~40和200之间，及其与卵巢功能不全的关系。有意义的数据描述了携带FMR 1前突变扩增的妇女的生殖障碍，包括卵巢早衰。突变前扩增和生殖障碍之间的联系是最近才发现的，因此目前还不了解这种突变导致妇女生殖能力改变的机制。我们的目标是确定模型，这将是有用的，在定义女性生殖FMR 1前突变的作用。拟议的项目有两个具体目标。目的1将利用现有的小鼠模型的脆性X前突变和充分表征女性生育能力。目的是评估与女性中记录的生殖参数类似的生殖参数，以确定小鼠模型的意义及其与生殖的关系。在目标2中进行的研究将创建携带针对颗粒、垂体前叶和卵母细胞的前突变扩增CGG重复序列的条件性敲入。对女性的研究表明，这些细胞类型中的每一种都可能受到前突变的影响，从而在导致卵巢功能不全中发挥作用。颗粒层、卵母细胞和垂体前叶构成了下丘脑-垂体-卵巢内分泌系统的关键组成部分，对正常生育力非常重要。单独针对每种细胞类型将使我们能够仔细评估每种细胞类型中前突变的贡献，因为它与生殖过程有关。利用链霉菌噬菌体C31（？）C31）位点特异性整合酶来指导转基因整合将用于产生条件性转基因。在靶向前突变小鼠的生产中，我们将产生条件性转基因小鼠，其将成为更大研究群体的工具，允许将前突变扩增靶向任何组织或细胞类型。我们有一个在女性生殖生物学、小鼠遗传学和脆性X患者群体方面具有专业知识的研究团队，我们将共同应对NIH的这一直接呼吁。随着这些研究的完成，我们将拥有全球和有针对性的前突变扩增小鼠模型，特别适合探索FMR 1前突变影响女性生殖系统的机制。

DESCRIPTION (provided by applicant): This project directly addresses the call by NIH for the development and characterization of models specifically suited to study the impact of FMR1 premutation on ovarian insufficiency. The Fragile X Mental Retardation 1 gene (FMR1) contains a series of approximately 30 CGG triplet repeats located in the 5' UTR. Mutational expansion of the number of CGG repeats to greater than 200 triplets leads to Fragile X Syndrome. The focus of the present studies is the premutation expansion of the CGG repeats to between ~40 and 200, and its association with ovarian insufficiency. Significant data describe reproductive insufficiencies including premature ovarian failure in women carrying the FMR1 premutation expansion. The association between pre- mutation expansion and reproductive insufficiencies was made recently and thus there is currently no understanding of the mechanisms whereby this premutation result in altered reproductive capacity in women. Our objective is to identify models that will be useful in defining the role of FMR1 premutation in female reproduction. The proposed project has two specific objectives. Aim 1 will take advantage of an existing mouse model of fragile X premutation and fully characterize female fertility. The objective is to assess reproductive parameters analogous to those documented in women in order to establish the significance of the mouse model and its relationship to reproduction. The studies carried out in Aim 2 will create conditional knock-ins carrying premutation expanded CGG repeats targeted to the granulosa, anterior pituitary, and oocyte. Studies in women indicate each of these cell types may be impacted by the premutation and thus play a role in the resulting ovarian insufficiency. The granulosa, oocyte, and anterior pituitary form key components of the hypothalamic-pituitary-ovarian endocrine system important for normal fertility. Targeting to each cell type individually will allow us to carefully assess the contribution of the premutation in each cell type as it relats to the reproductive process. A novel transgenesis method relying on the use of the Streptomyces phage C31 (?C31) site specific integrase to direct transgene integration will be used to generate the conditional transgene. In production of the targeted premutation mice we will generate a conditional transgenic mouse that will be a tool for the greater research community allowing for targeting of the premutation expansion to any tissue or cell type. We have an assembled research team with expertise in female reproductive biology, mouse genetics, and the fragile X patient population and together we are poised to address this directed call by NIH. With the completion of these studies we will have both global and targeted premutation expansion mouse models specifically suited to explore the mechanisms whereby FMR1 premutation impacts the reproductive system in women.