Differential aggregation and functional impairment induced by polyalanine expansions in FOXL2, a transcription factor involved in cranio-facial and ovarian development
Differential aggregation and functional impairment induced by polyalanine expansions in FOXL2, a transcription factor involved in cranio-facial and ovarian development
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DOI：
10.1093/hmg/ddm373
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发表时间：
2008-04-01
影响因子：
3.5
通讯作者：
Veitia, Reiner A.
中科院分区：
文献类型：
--
作者：
Moumne, Lara;Dipietromaria, Aurelie;Veitia, Reiner A.
聚丙氨酸（polyAla）束扩张与越来越多的人类疾病相关。在这里，我们已经进行了功能研究的polyAla扩增的转录因子FOXL 2的背景下，参与颅面和卵巢发育的影响。使用两个细胞模型，我们表明，FOXL 2聚丙氨酸扩增导致蛋白质的错误定位和聚集在一个长度依赖性的方式。含有细胞质染色的细胞的分数显示相对于polyAla道的长度的S形关系，这表明存在阈值长度，高于该阈值长度发生蛋白质错误定位。如果我们认为聚丙氨酸束越长，其错误折叠或诱导与细胞质组分的虚假相互作用的倾向就越高，那么这种阈值的存在可能是合理的。为了研究聚丙氨酸扩增的FOXL 2的核内动力学，我们在光漂白实验后进行荧光恢复。最出乎意料的结果涉及在运行中含有19个Ala残基的致病蛋白，其几乎是不动的，尽管该变体不呈现经典的聚集模式。荧光素酶测定和许多潜在的靶基因的真实的时间RT-PCR显示，polyAla扩增根据测试的靶启动子诱导不同的活性损失。我们为这些发现提供了分子解释。虽然我们的主要重点是多聚丙氨酸扩展蛋白的发病机制，我们讨论了潜在的相关性的polyAla长度变化的微观和宏观进化，因为含polyAla的蛋白质往往是转录因子。
Polyalanine (polyAla) tract expansions have been associated with an increasing number of human diseases. Here, we have undertaken a functional study of the effects of polyAla expansions in the context of the transcription factor FOXL2, involved in cranio-facial and ovarian development. Using two cellular models, we show that FOXL2 polyAla expansions lead to protein mislocalization and aggregation in a length-dependent manner. The fraction of cells containing cytoplasmic staining displays a sigmoidal relationship with respect to the length of the polyAla tract, suggesting the existence of a threshold length above which protein mislocalization occurs. The existence of such a threshold might be rationalized if we consider that the longer the polyAla tract is, the higher its tendency to misfolding or to inducing spurious interactions with cytoplasmic components. To study the intranuclear dynamics of polyAla-expanded FOXL2, we performed fluorescence recovery after photobleaching experiments. The most unexpected result concerned the pathogenic protein containing 19 Ala residues in the run, which was virtually immobile, although this variant does not present a classical aggregation pattern. Luciferase assays and real time RT-PCR of many potential target genes showed that polyAla expansions induce different losses of activity according to the target promoters tested. We provide molecular explanations for these findings. Although our main focus is the mechanisms of pathogenesis of polyAla-expanded proteins, we discuss the potential relevance of polyAla length variation in micro- and macroevolution because polyAla-containing proteins tend to be transcription factors.