Translocations/genes in Premature Ovarian Failure

卵巢早衰的易位/基因

• 批准号: 6815261
• 负责人: Ramaiah Nagaraja
• 金额: --
• 依托单位: NATIONAL INSTITUTE ON AGING
• 依托单位国家: 美国
• 资助国家: 美国
• 起止时间: 至
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/6815261
• 关键词: aging; chromosome translocation; developmental genetics; embryogenesis; female; gene deletion mutation; gene expression; genetic mapping; laboratory mouse; mammalian embryology; menopause; nucleic acid sequence; ovary disorder; sex chromosomes

About 1-3% of all women undergo precocious menopause, either never going through menarche or stopping menstruation by the mid-30's, rather than reaching the standard reproductive lifespan of about 50. A fraction of such instances of early-onset "premature ovarian failure (POF)" is genetic. A single locus on chromosome 3 is implicated in several families and in several isolated individuals with translocations or deletions that interrupt the DNA in that region. In collaboration with the group of Dr. G. Pilia, we isolated the gene, FOXL2, in which mutations cause POF and an eyelid malformation, and are analyzing its function; it appears to function as a rheostat, determining the number of follicles by the level of its function. We have recovered the mouse orthologue, Foxl2, and have generated a knockout to create a mouse model. We are beginning to characterize the resulting phenotype, which seems to mimic eyelid and ovarian features seen in women lacking one allele of FOXL2. A much larger group of translocations on the X chromosome, centering on a critical region of the long arm, have been associated with POF. We have prevously shown that based on the physical map we had constructed, there are at least 35 distinct X chromosome loci at which translocations can produce POF. We have begun further molecular analyses of the sequences spanning translocation breakpoints. Three have been analyzed in detail at the sequence level, and two of these fall outside of any gene, in regions of repetitive sequence elements. This increases the possibility that some X translocations act by interrupting chromosome dynamics during meiosis, whereas others may cause POF by the interruption of specific genes involved in follicle formation or stability. To help understand the failure of follicle formation and maintenance in POF, we analyzing the normal ovarian development in mouse using 15K cDNA microarray (the NIA array developed by the group of Dr. M. Ko (LG)), to assess the gene cohorts involved in ovary formation. We have thus far compared the profile of genes expressed in nascent ovary, from newborn mice in which ovarian follicles are just starting to be formed, with mature ovary, in which follicles are fully formed and compared them to those expressed in testes. Marker genes expressed in follicle cells only at birth, or in oocytes of nascent or in mature mice have been recovered for further functional studies. These will be analyzed along with genes whose function is sharply affected in hereditary POF, using the mouse model generated with disrupted Foxl2. In that model, the point of interruption of programmed and coordinated gene function will be assessed by determining the target genes under the control of Foxl2.

大约1-3%的女性经历了提前绝经，要么从未经历过月经初潮，要么在35岁左右就停止月经，而不是达到50岁左右的标准生育寿命。这种早发性“卵巢早衰（POF）”的一小部分是遗传的。3号染色体上的单个位点涉及几个家族和几个孤立的个体，其易位或缺失会中断该区域的DNA。与G. Pilia博士的团队合作，我们分离出了FOXL2基因，该基因的突变会导致POF和眼睑畸形，并正在分析其功能；它似乎起着变阻器的作用，通过其功能水平来决定卵泡的数量。我们已经恢复了小鼠的同源基因Foxl2，并产生了一个基因敲除来创建小鼠模型。我们正在开始描述由此产生的表型，它似乎模仿了缺乏FOXL2等位基因的女性的眼睑和卵巢特征。X染色体上更大的易位组，以长臂的关键区域为中心，与POF有关。我们之前已经证明，基于我们构建的物理图谱，至少有35个不同的X染色体位点易位可以产生POF。我们已经开始对跨越易位断点的序列进行进一步的分子分析。其中三个已经在序列水平上进行了详细分析，其中两个位于任何基因之外，位于重复序列元素的区域。这增加了一些X易位在减数分裂期间通过中断染色体动力学而起作用的可能性，而另一些则可能通过中断参与卵泡形成或稳定性的特定基因而导致POF。为了帮助理解POF中卵泡形成和维持的失败，我们使用15K cDNA微阵列（Dr. M. Ko （LG）团队开发的NIA阵列）分析小鼠正常卵巢发育，以评估参与卵巢形成的基因队列。到目前为止，我们已经比较了新生卵巢（卵泡刚刚开始形成的新生小鼠）和成熟卵巢（卵泡已经完全形成）中表达的基因图谱，并将它们与睾丸中表达的基因进行了比较。仅在出生时的卵泡细胞或新生或成熟小鼠的卵母细胞中表达的标记基因已被恢复用于进一步的功能研究。使用Foxl2中断产生的小鼠模型，这些基因将与在遗传性POF中功能受到严重影响的基因一起进行分析。在该模型中，将通过确定Foxl2控制下的靶基因来评估编程和协调基因功能的中断点。