Evidence for a fragile X messenger ribonucleoprotein 1 (FMR1) mRNA gain-of-function toxicity mechanism contributing to the pathogenesis of fragile X-associated premature ovarian insufficiency.
Evidence for a fragile X messenger ribonucleoprotein 1 (FMR1) mRNA gain-of-function toxicity mechanism contributing to the pathogenesis of fragile X-associated premature ovarian insufficiency.
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DOI：
10.1096/fj.202200468rr
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发表时间：
2022-11
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--
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脆性X相关性卵巢功能不全（FXPOI）是由位于X染色体上脆性X信使核糖核蛋白1（FMR 1）基因5′非翻译区（UTR）的CGG三核苷酸重复序列扩增引起的疾病家族之一。患有FXPOI的女性卵巢卵泡数量减少，导致闭经，雌激素水平低下，并在40岁之前丧失生育能力。FXPOI是由CGG序列扩展到55至200个重复之间的长度引起的，称为FMRI前突变，然而前突变驱动疾病发病机制的机制仍不清楚。存在两种主要假设，它们描述了mRNA毒性功能获得机制或基于蛋白质的机制，其中重复相关的非AUG（RAN）翻译导致产生称为FMRpolyG的异常蛋白质。在这里，我们通过异位表达CGG重复RNA和FMRpolyG蛋白，建立了FMR1前突变的体外颗粒细胞模型。我们发现，扩增的CGG重复RNA积聚在核内RNA结构中，这些聚集体能够引起显著的颗粒细胞死亡，而不依赖于FMRpolyG表达。使用一种创新的RNA下拉，基于质谱的方法，我们已经确定了在体外颗粒细胞中被CGG RNA聚集体特异性隔离的蛋白质，因此可能由于这种相互作用而被解除调节。此外，我们已经证明了在FMR 1前突变小鼠模型的卵泡中通过我们的RNA下拉鉴定的三种蛋白质（FUS，PA2G4和TRA2β）的表达减少。总的来说，这些数据为mRNA功能获得机制对FXPOI疾病生物学的贡献提供了证据。
Fragile X‐associated premature ovarian insufficiency (FXPOI) is among a family of disorders caused by expansion of a CGG trinucleotide repeat sequence located in the 5′ untranslated region (UTR) of the fragile X messenger ribonucleoprotein 1 (FMR1) gene on the X chromosome. Women with FXPOI have a depleted ovarian follicle population, resulting in amenorrhea, hypoestrogenism, and loss of fertility before the age of 40. FXPOI is caused by expansions of the CGG sequence to lengths between 55 and 200 repeats, known as a FMRI premutation, however the mechanism by which the premutation drives disease pathogenesis remains unclear. Two main hypotheses exist, which describe an mRNA toxic gain‐of‐function mechanism or a protein‐based mechanism, where repeat‐associated non‐AUG (RAN) translation results in the production of an abnormal protein, called FMRpolyG. Here, we have developed an in vitro granulosa cell model of the FMR1 premutation by ectopically expressing CGG‐repeat RNA and FMRpolyG protein. We show that expanded CGG‐repeat RNA accumulated in intranuclear RNA structures, and these aggregates were able to cause significant granulosa cell death independent of FMRpolyG expression. Using an innovative RNA pulldown, mass spectrometry‐based approach we have identified proteins that are specifically sequestered by CGG RNA aggregates in granulosa cells in vitro, and thus may be deregulated as consequence of this interaction. Furthermore, we have demonstrated reduced expression of three proteins identified via our RNA pulldown (FUS, PA2G4 and TRA2β) in ovarian follicles in a FMR1 premutation mouse model. Collectively, these data provide evidence for the contribution of an mRNA gain‐of‐function mechanism to FXPOI disease biology.
影响因子：
4.8
作者：
Dijkstra AA;Haify SN;Verwey NA;Prins ND;van der Toorn EC;Rozemuller AJM;Bugiani M;den Dunnen WFA;Todd PK;Charlet-Berguerand N;Willemsen R;Hukema RK;Hoozemans JJM
通讯作者：
Hoozemans JJM