Li Xin, Syed Ishana, Zhang Zhao, Adhikari Rashmi, Tang Dan, Ko SuHyuk, Liu Zhijie, Chen Lizhen
Barshop Institute for Longevity and Aging Studies, Department of Cell Systems and Anatomy, University of Texas Health Science Center at San Antonio, San Antonio, TX 78229, USA.
Department of Molecular Medicine, Mays Cancer Center, University of Texas Health Science Center at San Antonio, San Antonio, TX 78229, USA.
bioRxiv. 2024 Nov 3:2024.11.02.621395. doi: 10.1101/2024.11.02.621395.
Alternative splicing is a fundamental process that contributes to the functional diversity and complexity of proteins. The regulation of each alternative splicing event involves the coordinated action of multiple RNA-binding proteins, creating a diverse array of alternatively spliced products. Dysregulation of alternative splicing is associated with various diseases, including neurodegeneration. Here we demonstrate that CELF2, a splicing regulator and a GWAS-identified risk factor for Alzheimer's disease, binds to mRNAs associated with neurodegenerative diseases, with a specific interaction observed in the intron adjacent to exon 10 on Tau mRNA. Loss of CELF2 in the mouse brain results in a decreased inclusion of Tau exon 10, leading to a reduced 4R:3R ratio. Further exploration shows that the hinge domain of CELF2 possesses an intrinsically disordered region (IDR), which mediates CELF2 condensation and function. The functionality of IDR in regulating CELF2 function is underscored by its substitutability with IDRs from FUS and TAF15. Using TurboID we identified proteins that interact with CELF2 through its IDR. We revealed that CELF2 co-condensate with NOVA2 and SFPQ, which coordinate with CELF2 to regulate the alternative splicing of Tau exon 10. A negatively charged residue within the IDR (D388), which is conserved among CELF proteins, is critical for CELF2 condensate formation, interactions with NOVA2 and SFPQ, and function in regulating tau exon 10 splicing. Our data allow us to propose that CELF2 regulates Tau alternative splicing by forming condensates through its IDR with other splicing factors, and that the composition of the proteins within the condensates determines the outcomes of alternative splicing events.
可变剪接是一个基本过程，它有助于蛋白质的功能多样性和复杂性。每个可变剪接事件的调控都涉及多种RNA结合蛋白的协同作用，从而产生各种各样的可变剪接产物。可变剪接失调与包括神经退行性疾病在内的多种疾病相关。在这里，我们证明CELF2是一种剪接调节因子，也是全基因组关联研究确定的阿尔茨海默病风险因素，它与神经退行性疾病相关的mRNA结合，在Tau mRNA外显子10相邻的内含子中观察到特异性相互作用。小鼠大脑中CELF2的缺失导致Tau外显子10的包含减少，导致4R:3R比率降低。进一步研究表明，CELF2的铰链结构域具有一个内在无序区域（IDR），该区域介导CELF2的凝聚和功能。IDR在调节CELF2功能方面的功能通过其与FUS和TAF15的IDR的可替代性得到强调。使用TurboID我们鉴定了通过其IDR与CELF2相互作用的蛋白质。我们发现CELF2与NOVA2和SFPQ共同凝聚，它们与CELF2协同调节Tau外显子10的可变剪接。IDR内一个带负电荷的残基（D388）在CELF蛋白中保守，对CELF2凝聚物形成、与NOVA2和SFPQ的相互作用以及调节tau外显子10剪接的功能至关重要。我们的数据使我们能够提出，CELF2通过其IDR与其他剪接因子形成凝聚物来调节Tau可变剪接，并且凝聚物中蛋白质的组成决定了可变剪接事件的结果。
